=>
5. doesn't he -> isn't he ( dạng câu hỏi đuôi)
6. problem -> problems ( one of + N số nhiều)
7. didn't -> wouldn't ( câu điều kiện loại 2)
13. the last few year -> in the last few years.
14. to weed -> weeding ( câu bị động)
15. that -> those ( those + N số nhiều)