C2 to begin something开始;着手
We will commence building work in August of next year.我们将于明年8月开始破土动工。
Shall we let the meeting commence?我们开始开会,好吗?
[ + -ing verb ] Unfortunately, he commenced speaking before all the guests had finished eating.遗憾的是,没等所有客人都吃完,他就开始讲话了。