They were able to prevent SARS ________ by ________ the patients．
A.to spread…isolate
B.spreading…isolating
C.from spreading…isolate
D.having spread…isolating
网友回答
B解析动词prevent的用法是prevent sb from doing sth意思是“阻止／妨碍某人做某事（在这个词组中的介词from可以省略）”。prevent sb by doing sth意思是“通过某种手段阻止某人做某事”。