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:
Walking is a good form of exercise for both young and old.
2.在”There/It +be+ no use(good/help/need)”之后常用动名词做主语,而少用不定式,如:
It/There is no use crying over the split milk.
It/There is no help taking this medicine.
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:
There is no good for us to do that exercise.
3.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:How to solve the problem is a hot potato.
to do,一次性的动作。doing经常的行为。
不定式做主语一般指具体的某一动作,而动名词做主语多是泛指。如:Learning is necessary for all of us in this society。