Question

H1N1 control and prevention is a      to China as well as the whole world．

1. A.
   surprise
2. B.
   challenge
3. C.
   reaction
4. D.
   threat

Answer 1

B
本题考查名词辨析。句意：H1N1的预防与控制对中国以及整个世界来说都是一种难题。challenge 挑战;艰巨的事；threat to对…威胁，surprise to出乎…的意外， reaction to 对…的反应。