Question

老师好，请问是it is a waste of time doing 还是 to do sth

Answer 1

请问是it is a waste of time doing 还是 to do sth
是it's a waste of time doing sth
意思是：做某事浪费时间，是固定句型.
其中it为形式主语,真正的主语是动名词短语doing sth，置于句尾,
it is a waste of time句型后一般不用不定式短语to do sth.

Answer 2

doing
国定用法
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