Ⅱ. 单项填空（共15小题；每小题1分, 满分15分）
21. Beyond doubt, so much noise outside____him settling down to____his homework.
A. kept；do B. prevented；do
C. kept；doing D. prevented; doing
【解析】选D。考查动词的用法。prevent sb. (from)doing sth. 阻止某人做某事；settle down to doing sth. 静下心来做某事；keep sb. from doing结构中，from一般不省略。
