start doing 与start to do 的区别?

egin / start to do sth begin / start doing sth。1) 谈及一项长期活动或开始一种习惯时,使用doing。How old were you when you first started playing the piano?你几岁时开始弹钢琴?2) begin,start用进行时时,后面动词用不定式to do I was beginning to get angry。我开始生起气来。3) 在attempt,intend,begin,start 后接know,understand,realize这类动词时,常用不定式to do。I begin to understand the truth。我开始明白真相。4) 物作主语时 It began to melt。