非谓语动词中什么时候用不定式,什么时候用分词,什么时候用动名词?不是区分to do,to be doing,to have done ,to be done ,to have been done!而是选项中同时出现to be doing和doing或to have done和having done或to have been done和having been done时改选哪一个
问题描述：
非谓语动词中什么时候用不定式,什么时候用分词,什么时候用动名词?
不是区分to do,to be doing,to have done ,to be done ,to have been done!
而是选项中同时出现to be doing和doing
或to have done和having done
或to have been done和having been done时改选哪一个
答