They are busy ( ) a research ( ) environment A to,on B on,at

问题描述:

They are busy ( ) a research ( ) environment A to,on B on,at C with,on D with,at 选哪个 为什么
1个回答 分类:英语 2014-09-22

问题解答:

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选C.be busy with sth忙于某事,on sth 关于...
 
 
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