H1N1 flu from spreading, our government has taken some effective measures.
A. Prevent
B. Preventing
C. Prevented
D. To prevent
网友回答
A. Prevent
B. Preventing
C. Prevented
(答案→)D. To prevent
解析：本题的含义为我们的政府采取了一些有效的措施以防止H1N1禽流感蔓延，表示做某事的目的用动词不定式to do作目的状语，故本题选D。