各位，有几道英语题始终弄不明白，请帮帮忙。。。谢谢~
41.our classroom must be made_____all the time.
A.clean B.to clean C.cleaning D.cleans
44.the students_________an english class at 10:00 yesterday morning.
A.having B.were having C.had had D.had
52.you______worry about your son. He will be well soon.
A.needn’t to B.need to C.don’t need D.don’t need to
53.the famous professor taught us________ourselves.
A.how to train B.want to train C.how train D.what train
56.please tell him to call me__________.
A.as fast as possible B.as quick as possible
C.as quickly as possible D.as soon as possible
62.you mustn’t give up studying foreign languages for even a day. This underlined part means_______.
A.stop trying to do something B.continue C.hand up D.try
请您详细告知解题原因。。。谢谢！
参考答案:1.B,被动语态中的to要还原
2.B，有明确时间用过去进行时
3.D，needn't是情态动词否定，不加to。don't need是动词,必须加to
4.A，有宾语ourselves，所以用how不用what。（how to do sth./what to do)
5.D，一般都这么说
6.划线的应该是mustn’t give up吧，C，一定不放弃。
A是放弃（stop doing停止做某事，stop to do停止当前去做某事）