1.People plant a lot of flowers in Da Lat
=> A lot of flowers are planted in Da Lat
2.They have given Tom a present
=> Tom has been given a present
3.Does Mr.Green often take them to the cinema on Sundays?
=> Are they often taken to the cinema by Mr.Green on Sunday?
4.Do they hold a meeting every month?
=> Is a meeting held every month?
5.Have they asked you several questions?
=> Have you been asked several questions?
6.She is going to invite him to her birthday party.
=> He is going to be invited to her birthday party.
7.No one can do that work.
=> That work can't be done.
8.Who wrote it?
=> Who was it written by?
9.Did you send her a present yesterday?
=> Was she sent a present by you yesterday?
10.The builders were building the new bridge when we came.
=> The new bridge was being built when we came.
11.Does Tom always do his exercises carefully?
=> Are Tom's exercises always done carefully?
12.Her mother doesn't cook meals in the kitchen.
=> Meals weren't cooked in the kitchen by her mother.
13.The teacher punished Tom because of his laziness.
=> Tom was punished by the teacher because of his laziness.
14.Did Henry sing English songs beautifully?
=> Were English songs sung beautifully by Henry?
15.When did they open that hospital?
=> When was that hospital opened?
16.No one has made any comments on that event.
=> No comment has been made on that event.
17.What do they call the new hotel?
=> What was the new hotel called?
18.Nobody has seen him anywhere this week.
=> He hasn't been seen this week.
19.Did anyone see you come in?
=> Were you seen come in?
20.Has anyone ever taught you how to behave?
=> Have you ever been taught how to behave?
21.They have awarded the best student a scholarship.
=> The best student has been awarded a scholarship.