21. She had a good _____ of foreign languages, so she had no difficulty working for the EXPO in Shanghai, China.
A. requirement B. command C. request D. series
【解析】选B。考查固定用法。have a good command of意为“精通”。本句意为“她精通外语，因此她为上海世博会工作没有困难。”
22. He was so _____ his daughter’s safety that he drove to her school immediately after he got off the train.
A. concerned about B. tired of
C. fond of D. disappointed at
【解析】选A。be concerned about“担心，担忧，关心”。句意：他那么担心女儿的安全以至于下了火车就驶向了她的学校。
