I think what you are doing is _______(waste) time.

问题描述:

I think what you are doing is _______(waste) time.

wasting i think 为插入语,可以直接去掉,不用考虑它的成分.整个句子的主语为 what are you doing,谓语为 is.我们都知道一个句子中若无连词是不可以同时存在两个动词的,所以我们要用wasting.如果没有is 则填 wastes