4. slip

【点拨】slip作动词时，意为：①滑倒，滑跤；②滑落，脱落；③溜，悄悄疾行（常与in, out, away连用）；④迅速放置，悄悄塞，偷偷放；⑤下降，退步，变差。如：

Polly slipped over on the ice.

Steven's hat had slipped over one eye.

Just slip out of the room while nobody's looking.

Ann slipped the book into her bag.

Standards have slipped in many parts of the industry.

【考例1】Diane slipped into the water and dived happily until white caps began rolling in and it became harder to swim against the current (水流). (江西 2013完形填空)

【考例2】Somehow the boys had slipped away to the back lot with their kites. (浙江 2011阅读理解D篇)