8.11 begin(start) doing/to do begin / 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？ http://yingyu.chazidian.com 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.