III/ rewrite these sentences, using present perfect tense

1. She began to learn English 3 years ago

->she has learned English for 3 years

2. He started playing tennis when he was 6

-> he has played tennis since he was 6

3. He began to work for this company in 2002

-> my brother has worked for this company since 2002

4. He started collecting stamps 4 months ago

-> he has collected stamps for 4 months

5. The last time i saw him was 2 weeks ago

-> i haven't seen him for 2 weeks

6. The last time they visited Hue was in 1999

-> they haven't visited Hue since 1999

7. We last ate in that restaurant in January

-> we haven't eaten in that restaurant since January

8. She last came here 3 months ago

-> she hasn't come here for 3 months

9. It's a long time since i last wrote to her

-> i haven't written to her for a long time

10. It's many years since we last our aunt

-> we haven't met our aunt for many years

III/ rewrite these sentences, using present perfect tense

1. She began to learn English 3 years ago

->she has..learned English for 3 years.

2. He started playing tennis when he was 6

-> he has.played tennis since he was 6.

3. He began to work for this company in 2002

-> my brother has..worked for this company since 2002..

4. He started collecting stamps 4 months ago

-> he has.collected stamps for 4 months..

5. The last time i saw him was 2 weeks ago

-> i haven't.seen him for 2 weeks..

6. The last time they visited Hue was in 1999

-> they haven't.visited Hue since 1999..

7. We last ate in that restaurant in January

-> we haven't .eaten in that restaurant since January..

8. She last came here 3 months ago

-> she hasn't come here for 3 months

9. It's a long time since i last wrote to her

-> i haven't written to her for a long time

10. It's many years since we last our aunt

-> we haven't met our aunt for many years

1. By the time I go to bed tonight, I ______my work for the day.

          A. will finish         B. have finished               C. will have finished          D. finish

2.  Simon lives and works in France but he _____a holiday with his family in Australia now.

           A. is spending       B.is going to spend          C. will spend           D. spends           

3. My sister ____ for me at the train station when I arrive tomorrow.

          A. will wait            B. will have waited         C. will be waiting     D. is waiting  

4. The lecturer _______taught IELTS to us appeared on TV last Saturday.

          A. that                     B. which                          C. whom                   D. whose

5. Tom said everything________ ready when the match________.

          A. will be/ starts     B. would be/ started        C. is / started          D. will be/ started

6. He asked me what___________.

          A. I had done         B. had I done                   C. was I doing        D. have I have

7. They don’t allow ______ at gas station.

     A. smoke              B. to smoke                    C. smoking           D. smoked

8. Peter ______ from Paris. He ______ three weeks ago with his friends.

     A. will just return/ flies                                B. has just returned/ flew         

     C. had just returned/ flew                             D. is just returning/ was flying

9. Jim wishes he _______ Jane to his birthday party last night.

      A. invited             B. would invite               C. have invited      D. had invited

10. My brother was feeling tired last night, so he went to bed_______ usual.

     A. more early than                                       B. as early as                 

     C. more earlier as                                        D. earlier than

11. China is the country with_______ population.

     A. the larger          B. the more large            C. the largest         D. the most large

12. Her grandfather’s illness was_______ we thought at first.

     A. more seriously as                                    B. as seriously as

     C. more serious than                                    D. as serious than

13. His house is _______ mine.

     A. twice as big as                                        B. as twice big as

     C. as two times big as                                  D. as big as twice

14. He talked about the books and the authors______ interested him.

     A. who                 B. that                            C. which               D. whom

15. Sunday is the day______ I go to Water park with my kinds.

     A. when                B. where                         C. why                  D. which

16. The lady____ son went on a picnic with us last weekend is a teacher at our school.

     A. who                 B. whom                        C. whose              D. that

17. This is the place______ the battle took place ten years ago.

     A. which               B. in where                     C. where               D. from where

18. Oxford, ______ attracts many tourists, is often crowded in the summer.

     A. that                  B. which                         C. whose               D. where

19. My parents wouldn't _______ to the party.

          A. allow me go      B. allow me to go            C. allow me going D. allow to go

20. We are going to have my house _______ tomorrow morning.

          A. paint                 B. painting                      C. painted             D. to be painted

21. The worker was _______ his boss expected, so he was offered a raise.

     A. more hard-working                                  B. as hard-working than

          C. more hard-working than                          D. more hard-working as

22. When Carol _______ last night, I ______ my favorite show on television.

     A. was calling / watched                              B. called / have watched

          C. called / was watching                              D. had called / watched

23. In the past, people _______ to the beach more often.

          A. have gone         B. used to go                   C. were going        D. had gone

24. We _______ touch since we _______ school three years ago.

     A. lost / have left                                         B. have lost / leave

          C. have lost / left                                          D. were losing / had left

25. John asked me _______ interested in any kind of sports.

          A. if I were            B. if were I                     C. if was I             D. if I was

26. John asked me _______ that film the night before.

          A. that I saw          B. had I seen                   C. if I had seen      D. if had I seen

27. She asked _______.

     A. where was her umbrella                           B. where her umbrella was

          C. where were her umbrella                          D. where her umbrella were

28. _______ by your father?

     A. Did that book write                                 B. Did that book written

          C. Was that book written                              D. Was that book be writing

29. This car _______.

     A. was manufactured in Japan by Toyota last year

     B. was manufactured by Toyota last year in Japan

     C. was manufactured last year in Japan by Toyota

          D. last year was manufactured by Toyota in Japan

30. When _______?

     A. were computers used first                        B. were computers first used

          C. did computers first use                             D. are computers first using

31. I would like a ____________ table

A. beautiful wooden round                          B. round beautiful wooden

C. beautiful round wooden                           D. wooden beautiful round

32. Thomas wore a ____________ shirt yesterday.

A. new white lovely cotton                          B. lovely new white cotton

C. lovely cotton new white                          D. new white cotton lovely

33. I have just bought an ____________ painting

A. interesting old French                             B. interesting French old

C. old French interesting                              D. old interesting French

34. He is living a ____________ house

A. wooden small old                                    B. wooden old small

C. small old wooden                                    D. small wooden old

35. A ____________university

A. modern Australian new                           B. new modern Australian

          C. new Australian modern                           D. modern new Australian

Chào em, em tham khảo nhé!

1. By the time I go to bed tonight, I ______my work for the day.

A. will finish         B. have finished       C. will have finished         D. finish

2.  Simon lives and works in France but he _____a holiday with his family in Australia now.

A. is spending     B.is going to spend   C. will spend      D. spends           

3. My sister ____ for me at the train station when I arrive tomorrow.

A. will wait       B. will have waited         C. will be waiting     D. is waiting  

4. The lecturer _______taught IELTS to us appeared on TV last Saturday.

A. that               B. which                         C. whom                   D. whose

5. Tom said everything________ ready when the match________.

A. will be/ starts     B. would be/ started        C. is/started        D. will be/ started

6. He asked me what___________.

A. I had done         B. had I done         C. was I doing        D. have I have

7. They don’t allow ______ at gas station.

A. smoke              B. to smoke               C. smoking           D. smoked

8. Peter ______ from Paris. He ______ three weeks ago with his friends.

A. will just return/ flies                                B. has just returned/ flew    

C. had just returned/ flew                           D. is just returning/ was flying

9. Jim wishes he _______ Jane to his birthday party last night.

A. invited             B. would invite           C. have invited      D. had invited

10. My brother was feeling tired last night, so he went to bed_______ usual.

A. more early than                                       B. as early as                 

C. more earlier as                                        D. earlier than

11. China is the country with_______ population.

A. the larger     B. the more large       C. the largest       D. the most large

12. Her grandfather’s illness was_______ we thought at first.

A. more seriously as                                    B. as seriously as

C. more serious than                                   D. as serious than

13. His house is _______ mine.

A. twice as big as                                        B. as twice big as

C. as two times big as                                 D. as big as twice

14. He talked about the books and the authors______ interested him.

A. who                 B. that                            C. which               D. whom

15. Sunday is the day______ I go to the Water park with my kids.

A. when                B. where                         C. why                  D. which

16. The lady____ son went on a picnic with us last weekend is a teacher at our school.

A. who                 B. whom                        C. whose              D. that

17. This is the place______ the battle took place ten years ago.

A. which               B. in where                C. where               D. from where

18. Oxford, ______ attracts many tourists, is often crowded in the summer.

A. that                  B. which                         C. whose               D. where

19. My parents wouldn't _______ to the party.

A. allow me go      B. allow me to go    C. allow me going    D. allow to go

20. We are going to have my house _______ tomorrow morning.

A. paint                 B. painting         C. painted             D. to be painted

21. The worker was _______ his boss expected, so he was offered a raise.

A. more hard-working                                  B. as hard-working than

C. more hard-working than                       D. more hard-working as

22. When Carol _______ last night, I ______ my favorite show on television.

A. was calling/watched                                B. called / have watched

C. called/was watching                              D. had called/watched

23. In the past, people _______ to the beach more often.

A. have gone         B. used to go            C. were going        D. had gone

24. We _______ touch since we _______ school three years ago.

A. lost / have left                                         B. have lost / leave

C. have lost/left                                           D. were losing/had left

25. John asked me _______ interested in any kind of sports.

A. if I were            B. if were I                   C. if was I             D. if I was

26. John asked me _______ that film the night before.

A. that I saw          B. had I seen        C. if I had seen      D. if had I seen

27. She asked _______.

A. where was her umbrella                           B. where her umbrella was

C. where were her umbrella                          D. where her umbrella were

28. _______ by your father?

A. Did that book write                                 B. Did that book written

C. Was that book written                            D. Was that book be writing

29. This car _______.

A. was manufactured in Japan by Toyota last year

B. was manufactured by Toyota last year in Japan

C. was manufactured last year in Japan by Toyota

D. last year was manufactured by Toyota in Japan

30. When _______?

A. were computers used first                    B. were computers first used

C. did computers first use                         D. are computers first using

31. I would like a ____________ table

A. beautiful wooden round                          B. round beautiful wooden

C. beautiful round wooden                       D. wooden beautiful round

32. Thomas wore a ____________ shirt yesterday.

A. new white lovely cotton                          B. lovely new white cotton

C. lovely cotton new white                          D. new white cotton lovely

33. I have just bought an ____________ painting

A. interesting old French                          B. interesting French old

C. old French interesting                              D. old interesting French

34. He is living a ____________ house

A. wooden small old                                    B. wooden old small

C. small old wooden                                    D. small wooden old

35. A ____________university

A. modern Australian new                           B. new modern Australian

C. new Australian modern                           D. modern new Australian

Chúc em học tốt và có những trải nghiệm tuyệt vời tại hoc24.vn!

III/ rewrite using present perfect tense

1. She began to learn English 3 years ago

-> she has learnt English for 3 years

2. They started playing tennis when they were 6

-> they have played tennis since they were 6

3. He began to work for this company in 2002

-> my brother has worked for this company since 2002

4. He started collecting stamps 4 months ago

-> he has collected stamps for 4 months

5. The last time i saw him was 2 weeks ago

-> i haven't seen him for 2 weeks

6. The last time he visited Hue was 4 years ago

-> he hasn't visited Hue for 4 years

7. We last ate in that restaurant in January

-> we haven't eaten in that restaurant since January

8. She last came here 3 months ago

-> she hasn't come here for 3 months

9. It is a long time since i last wrote to her

-> i haven't written to her for a long time

10. It is many years since we last met out uncle

-> we haven't met our uncle for many years

11. She last wore this dress at her 14th birthday

-> she hasn't worn this dress since her 14th birthday

12. Alex began to learn Vietnamese last months

-> alex has learnt Vietnamese since last month

13. She last wrote to me 5 months ago

-> she hasn't written to me for 5 months

14. It is over 10 years since we visited Paris

-> we haven't visited Paris for over 10 years

15. The last time i went finishing was in 2004

-> i haven't gone finishing since 2004

PTHH: \(Al_2O_3+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2O\)

Ta có: \(\left\{{}\begin{matrix}m_{H_2SO_4}=588\cdot5\%=29,4\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{29,4}{98}=0,3\left(mol\right)\\n_{Al_2O_3}=\dfrac{20,4}{102}=0,2\left(mol\right)\end{matrix}\right.\)

Xét tỉ lệ: \(\dfrac{0,2}{1}>\dfrac{0,3}{3}\) \(\Rightarrow\) Al₂O₃ còn dư

\(\Rightarrow n_{Al_2\left(SO_4\right)_3}=0,1\left(mol\right)=n_{Al_2O_3\left(dư\right)}\)

\(\Rightarrow C\%_{Al_2\left(SO_4\right)_3}=\dfrac{0,1\cdot342}{20,4+588-0,1\cdot102}\cdot100\%\approx5,72\%\)

1. She has not came back to her hometown for 4 years.

2. He has worked as a bank clerk for 3 months.

3. I has just cut my hair since november.

4. We have not called each other for 5 month.

5. When have you had it?

\(:>>\)

am wearing/ have/ hurts/ have used/ haven't improved

IV/ rewrite each sentence, beginning as shown , so that the meaning stays the same

1. You should learn this lesson carefully

-> i would rather you learnt this lesson carefully

2. The Chinese invented paper

-> paper was invented by the chinese

3. A new school is going to be built for the poor

-> they are going to build a new school for the poor

4. The fishermen caught only a few fish

-> only a few fish were caught by The fishermen

\(d,ĐK:x\ge1\\ PT\Leftrightarrow\sqrt{x-1}=2+\sqrt{x+1}\\ \Leftrightarrow x-1=2+x+1+4\sqrt{x+1}\\ \Leftrightarrow4\sqrt{x+1}=-4\Leftrightarrow x\in\varnothing\left(4\sqrt{x+1}\ge0\right)\\ g,ĐK:x\ge\dfrac{1}{2}\\ PT\Leftrightarrow x+\sqrt{2x-1}+x-\sqrt{2x-1}+2\sqrt{\left(x+\sqrt{2x-1}\right)\left(x-\sqrt{2x-1}\right)}=2\\ \Leftrightarrow2x+2\sqrt{x^2-2x+1}=2\\ \Leftrightarrow\sqrt{\left(x-1\right)^2}=\dfrac{2-2x}{2}=1-x\\ \Leftrightarrow\left|x-1\right|=1-x\\ \Leftrightarrow\left[{}\begin{matrix}x-1=1-x\left(x\ge1\right)\\x-1=x-1\left(x< 1\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\left(tm\right)\\x\in R\end{matrix}\right.\)