21) stop to do sth 与 stop doing sth
1. stop to do sth 意为停下来去做某事。如：
The students stop to listen to their teacher.
学生们停下来去听他们老师讲话。
2. stop doing sth 意为停止做某事。如：
The students stopped talking. 学生们停止了谈话。
与它们相反的句式是：go on to do sth 继续做某事（与刚才一事不同）
和 go on doing sth 继续做某事（与刚才同一件事）。如：
He finishes his homework and goes on to study English.
他完成了作业，接着继续去念英语。
They went on playing games. 他们继续玩游戏。