change the following sentences into passive voice
đổi những câu sau thành giọng bị động
1 i clean the floor evary day
2 my mother bought this dress this morning
3 she did this exercise two days ago
4 they will send him abroad to study
5 she used this room
6 someone stole my bike yesterday
7 he received a letter from his parents
8 she will buy a new house
9 they aren't building my house
10 hecould solve the math problem easily
11 my mother waters these flowers every morning
12 nam invited hoa to his birthday party last night
13 her mother is preparing the dinner in the kitchen
14 we should clean our teeth twice a day
15 our teacher has explained the problem care fully
16 they are going to buy this house
17 he will visit his parents next month
18 the director didn't phone the secretary this morning
19 nam broke the window yesterday morning
20 they were doing the test at 3 p.m yesterday