slip: 溜;滑倒;滑落;脱落
1.I waited my chance and slipped out when no one was looking. 我等待时机，趁没人注意时溜了出去。
2.His hat had slipped over one eye. 他的帽子滑落下来遮住了一只眼睛。
fall: 落下;落后;跌倒;
1.The knife fell from her nerveless fingers. 刀从她无力的手里落下。
2.She fell back towards the end of the race.赛跑快结束时她落后了。
