呵呵``再来几个初三的英语问题哈·!

1.we don't clean the classroom every day.
The classroom isn't cleaned every day.
2.We keep the noise under 50dbs here.
The noise is kept under 50dbs here.
3.Did they plant many fruit trees on the hill last spring?
Many fruit trees were planted on the hill last spring?
4.Someone saw him swim in Shiyan Lake yesterday.
He is seen to swim in Shiyan Lake yesterday.
5.Do many people visited our school every day
Is our school visited by many people every day?
6.The flying disk was invented by college students.
College students invented the flying disk.
7.Was the special pen invented by Zhang Jie?
Did Zhang Jie invent this special pen?
8.Are the cows milked by them every day
Do they milk the cow every day?
9.Bicycles aren't produced by them in this factory.
They don't produce bicycles in this factory.
10.Is French taught by them in this college?
Do they teach French in this college?