Unstable crack propagation

unstable [ʌn'stebl]

adj. 不稳固的;不坚定的;易变的;反复无常的;

un不+stable稳定, 具有某种性质的 → 不牢固的, 不稳定的

crack [kræk]

vt. 破裂，打开;（使…）开裂;说（笑话）;开瓶; vi. 断裂，折断;碎裂声，爆裂声;镜子破裂了;失去控制，衰退; n. 裂缝;试图;缝隙;（可听到响声的）重击; adj. 训练有素的;技艺高超的;优秀的;一流的;

propagation [,prɑpə'geʃən]

n. 传播，传输，蔓延，扩展，波及深度;〔生〕繁殖法，〔地〕传导;宣传;培养;

pro 很多 +pag=pact紧的+ation 表名词 →人或物的密度很大→传播，繁殖，增殖

This show has gotten rave reviews.

这场演出好评如潮。

He licks his friend.

他舔着他的朋友。

OK, everyone. Less noise, please! Gather round and listen carefully. First we are going to search the beach and the rock pools. Let me remind you what we are looking for: seaweeds, fish, plants, all living things. When you find anything, make a note where

00在这里集合，游泳之后再吃午餐。别着急！我们有足够的时间。