把下列句子转换成被动语态You can play computer games if you finish you ho

把下列句子转换成被动语态
You can play computer games if you finish you homework
You can play computer fames if your ____ ____ ____
Does Helen often write short stories for children?
____ short stories often ____ ____ Helen for children.
Tom worked out the plan yesboard.
The plan ____ ____ ____ by Tom yesterday.
Where did they buy the new keyboard?
____ ____ th enew keyboard ____?
Did the students turn on the television just now?
____ the television ____ ____ by the students just now?
用所给词的适当形式填空.
That museum____(build)three tears ago.
Our classroom____(shoyld clean)every day.
That math problem____(cannot work)out in five minutes.
How many trees____(plant)since 1999?
More water____(may carryto thatcountry soon.