何时用不定式何时用分词和动名词Ⅰ
动名词和不定式做主语的相同点1
不定式短语和动名词做主语时,常常为了保持句子的平衡,用it来做形式主语,如:ItisnoteasytolearnEnglishwell
Itisnouseaskinghimforhelp
如果主语用了不定式,表语和宾语也要用不定式;主语用了动名词,表语和宾语也要用动名词,这在英语中称为对称性,如:Toseeistobelieve
=Seeingisbelieving
(眼见为实)(85)Itisbettertostayhomethan_A__out
goingC
动名词和不定式做主语的不同点1
不定式做主语常表示具体的某一动作;表示泛指或一般的抽象的概念时,多用动名词,如:(92)_B_isagoodformofexerciseforbothyoungandold
ThewalkB
WalkingC
TowalkD
在”There/It+be+nouse(good/help/need)”之后常用动名词做主语,而少用不定式,如:It/Thereisnousecryingoverthesplitmilk
It/Thereisnohelptakingthismedicine
★但是如果该句型中用了for引出不定式的逻辑主语,就只能用不定式,如:(93)Thereisnogoodforustodothatexercise
不定式可以和when,where,how,what,whether等连用,在句子中做主语,宾语和表语,而动名词则不能,如:Howtosolvetheproblemisahotpotato
Wheretoputtheboxseemshardtodecide
Whethertodoithasn’tbeendecided
Whattodonext