请教手法和公式

ccbreal

cave
n.[C]
1. 洞穴,洞窟
Our forefathers once lived in caves.
我们的祖先曾在洞穴居住。
2. 塌落(处)
vt.
1. 在...挖洞穴
2. 使屈服;使崩溃
3. 使塌落;使内陷[(+in)]
The top of the car was caved in by the impact.
那个冲击使得车顶塌了。
vi.
1. 塌落,倒坍[(+in)]
Our cellar caved during the earthquake.
地震时,我们的地窖塌陷了。
2. 【口】屈服,投降[(+in)][(+to)]
The school committee finally caved in to the demands of parents and teachers.
在家长和老师的要求下,学校委员会最后终于屈服了。