V-ing做主语好像可以等于to+V原形 请问他们有什么区别啊

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:
_B_ is a good form of exercise for both young and old.
A. The walk B. Walking C. To walk D. Walk
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.
Where to put the box seems hard to decide.
Whether to do it hasn’t been decided.
What to do next is up to you.