1. She last came back to her hometown 4 years ago.
   The last time + S + V (QKĐ) + was + time
   = S + last + V (QKĐ) + time
2. We have to wear a helmet when driving.
   allow + to-V = have to-V
3. I prefer living in a smart city to living in the countryside.
   prefer + V-ing to V-ing: thích cái gì hơn cái gì
4. Learning English is really quite easy.
   It is + adj + to-V = V-ing + is + adj
5. Taken to the garage, the car was repaired within an hour.
   Rút gọn 2 câu có cùng chủ ngữ với quá khứ phân từ

31. she has not gone back since

32. we must wear helmet

33. i perfect to live in a smart city than in the countryside

34. learning english is not very difficult

35. the car was taken to the garage and was repaired within an  hour