He asked if I lent them his camera.

Hình như đúng rồi á :)

20. → Peter has given up encouraging Mary to take part in the competition.

IV.
21. eaten
22. grows
23. thousands
24. with 
25. beautiful
26. in
27. Instead
28. as

V.
29. A
30. D
31. C
32. A
33. C

VI.
34. I wish my sister would come to my birthday party tomorrow.
35. In the end, I decided not to buy the camera because it is too expensive.

VII.
36. A
37. D
38. A
39. B
40. B

saw - was trying
- Khi một hành động đang diễn ra thì bị một hành động khác xen vào. 
Cấu trúc: When + S₁ + V(past simple), S₂ + V(past continuous).  
Không biết giải thích s nữa :)

\(y+\dfrac{2}{3}=\dfrac{5}{2}\)

\(\xrightarrow[]{}y=\dfrac{5}{2}-\dfrac{2}{3}\)
 

\(\xrightarrow[]{}y=\dfrac{11}{6}\)
 

\(3\dfrac{4}{5}-y=\dfrac{18}{5}\)
 

\(\xrightarrow[]{}\dfrac{19}{5}-y=\dfrac{18}{5}\)

\(\xrightarrow[]{}y=\dfrac{19}{5}-\dfrac{18}{5}\)
 

\(\xrightarrow[]{}y=\dfrac{1}{5}\)

\(y-4\dfrac{5}{6}=2\dfrac{1}{6}+\dfrac{5}{6}\)
 

\(\xrightarrow[]{}y-\dfrac{29}{6}=\dfrac{13}{6}+\dfrac{5}{6}\)
 

\(\xrightarrow[]{}y-\dfrac{29}{6}=3\)
 

\(\xrightarrow[]{}y=3+\dfrac{29}{6}\)
 

\(\xrightarrow[]{}y=\dfrac{47}{6}\)

Việt Nam - đất nước 

a, \(\dfrac{7}{8}\times3+\dfrac{5}{12}\)

\(=\dfrac{21}{8}+\dfrac{5}{12}\)

\(=\dfrac{63}{24}+\dfrac{10}{24}\)
 

\(=\dfrac{73}{24}\)
 

\(\dfrac{4}{5}+\dfrac{7}{10}-\dfrac{1}{2}\)

\(=\dfrac{8}{10}+\dfrac{7}{10}-\dfrac{5}{10}\)
 

\(=\dfrac{1}{2}\)

 

\(\dfrac{6}{9}:\left(\dfrac{2}{3}:3\right)\)

\(=\dfrac{6}{9}:\left(\dfrac{2}{3}\times\dfrac{1}{3}\right)\)
 

\(=\dfrac{6}{9}:\dfrac{2}{9}\)
 

\(=\dfrac{6}{9}\times\dfrac{9}{2}\)
 

\(=3\)

Tổ quốc - giang sơn

\(56-6\left(7-x\right)=50\)
\(\xrightarrow[]{}6\left(7-x\right)=56-50\)
\(\xrightarrow[]{}6\left(7-x\right)=6\)
\(\xrightarrow[]{}7-x=6:6\)
\(\xrightarrow[]{}7-x=1\)
\(\xrightarrow[]{}x=7-1\)
\(\xrightarrow[]{}x=6\)

Hinh nhu loi 
 

Put the verbs into the correct tenses:
1. _____Did you have____ (you/have) a nice time in Rome?
2. ______Have you finished___ (you/finish) your homework yet?
3. He ___has been___(be) at his computer for six hours.
4. How long ____has she had_____(she/have) that car?
5. How many people (die) ____died_____ in the fire yesterday?
6. I ____don't know____ (not/ know) much about art, but I like some artists.
7. I _____had been waiting____(wait) for ages when finally the bus arrived.
8. I (receive) ___received____ a postcard from Jane yesterday.
9. I (correct) ____have been correcting____ all morning, I'm exhausted.
10. I (never/be) ___have never been___ sailing, what's it like?
11. It was late. Most of the shops (close) _____closed____.

12. It (rain) ___was raining___ when I got up this morning.
13. Janet ___is starting__ (start) a new job in September.
14. Nelly (have) ____is having_____ a great time in New York at the moment.
15. She was cooking dinner when we (arrive) _____arrived____.
16. She (just/come) _____has just came____ back from a Mediterranean cruise.
17. My husband (be) ____is_____ free for most of the afternoon.
18. The children were tired because they (swim) _had been swimming___ in the pool all afternoon.
19. They ____are going____(go) to spend six weeks in the USA.
20. We can use the car, I (repair) ___have repaired__ it. 
21. We were tired because we (be) ____had been_____ to a party the night before.
22. We ____were_____(be) too late for the train, it had just left.
23. When I got the airport I realized I (forget) ___had forgotten_____ my passport.
24. As soon as they (arrive) ____arrived____ we had dinner.
25. When they were driving home last night they (see) ___saw____ a terrible accident.
26. Where _____does Robert live____ (Robert/ live) now?
27. Who (Mandy/talk) _____is Mandy talking______ to?
28. What would he have done if he (be) ____were___ there?
29. I am very sorry but I (not finish) ____haven't finished_____ reading the book yet.
30. She (be) ___has been___ ill since last Monday. She won't be able to go to the sea - side next week - end.