Ⅱ. 单项填空（共15小题；每小题1分, 满分15分）
21. They claimed that_____1, 000 factories closed down during the economic crisis.
A. properly B. approximately
C. independently D. considerably
【解析】选B。考查副词词义辨析。句意：他们声称在经济危机期间大约有1 000家工厂倒闭了。properly合适地，恰当地；approximately大约，近似地；independently独立地；considerably大量地，根据句意选B。
