VI: 41. Learning english is very difficult (It is adj to V=V-ing is adj)

42. I have left school for 20 years (it is +.. years since I V-qk=I have V-pp for...years)

43. A new house has just bought by us (bị động HTHT)

44. Nam said he had to do all the housework then (lùi thì must-.had to, now->then)

45. You can type the letter right now, can't you? (câu hỏi đuôi)

46. Speaking english is very useful (câu 41)

47. He stopped smoking three years ago (stop V-ing: ngừng hẳn làm gì)

48. A new computer has just been bought by my father (bị động HTHT)

49.  He asked Lan who had phoned her the day before (lùi thì QKĐ->QKHT, yesterday->the day before_

50. Although the weather was bad, they had a picnic (although+a clause=in spite of+N/V-ing)