stop to do 停止，中斷做某事后去做另一件事。
stop doing 停止做某事。
They stop to smoke a cigarette. 他們停下來，抽了根煙。
I must stop smoking. 我必須戒煙了。
典型例題
She reached the top of the hill and stopped ___ on a big rock by the side of the path.
A. to have rested B. resting C. to rest D. rest
答案：C。由題意可知，她到了山頂，停下來在一個路邊的大石頭上休息。因此，應選擇"stop to do sth. 停下來去做另一件事"。而不僅僅是爬山動作的終止，所以stop doing sth.不正確。
