重点讲解：
1. come back 回来；
例句：He came back in the late afternoon.
他在傍晚回来。
2. think of 想到；想起；想出；
例句：She was pained to think of them still living such a miserable life.
想到他们还过着这样悲惨的生活，她心里很难受。
3. try out 试验；测验；
例句：She knew I wanted to try the boat out at the weekend.
她知道我周末想开船出去试一下。
4. say it all 清楚说明事实；明确表达（…的）感觉；
例句：This is my third visit in a week, which says it all.
这是我一周内第3次拜访，这说明了一切。