IV
1. c ( quá khứ đơn ) 2. b ( different from: khác với ) 3. a ( khách hàng )
4. b ( for example : ví dụ ) 5. a ( mệnh đề quan hệ )
V
31. that old house has jusst been sold
32. although the weather was bad, they had a....
33. a new mall will be built here
34. if he doesn't take these pills, he won't...
35. although he works hard, he can't....
VI
36. if it doesn't rain tomorrow, i will go camping with my friends
37. if i met ailien from outer space, i would invite them home to talk
38. i have never travelled by air
39. the students are studying for exam now
40. it was such a cold day that we decide not to go out
