使用区别如下:
表示长期活动或一种习惯性动作时,使用doing, 例句:
How old were you when you first started playing the piano? 你几岁时开始弹钢?
start用进行时时,因为已经带有ing,后面动词用不定式to do,例句:
I was beginning to get angry。 我开始生起气来。
start 后接know, understand, realize这类动词时,常用不定式to do,例句:
I begin to understand the truth。 我开始明白真相。
物作主语时 ,例句:
It began to melt。