第1个回答 2008-09-29
They spend two hours every night on their homework.
Thay spend two hours every night in doing their homework.
It takes them half an hour to do homework every night.
第2个回答 2008-09-29
你好,很高兴能帮你解答.
They spend half an hour doing their homework every night.
=They spend half an hour on their homework every night.
=It took them half an hour to do their homework every night.
第3个回答 2008-09-29
they take half an hour to do homework every evening.
第4个回答 2008-09-29
They spend at least half hour on their homework every night.
第5个回答 2008-09-29
They spend half an hour on doing assignment(homework) every night.