21. These soldiers never _____ to any trouble that happened during their rescue after the earthquake.
A. gave in B. gave up C. gave off D. gave out
【解析】选A。句意为：这些士兵从未向地震后抢救过程中出现的任何困难屈服过。give in屈服；give up放弃；give off放出、发出; give out分发；精疲力竭。
22. The audience _____ laughing when the speaker made a face. A. burst into B. burst out
C. burst with D. burst on
【解析】选B。句意：当演讲者做了一个鬼脸时观众们哄堂大笑起来。burst into+n. =burst out doing，故选B。burst with 充满；burst on突然显现。
