大全748一个干扰项提问

748.     The fear of rabies is well founded; few people are known to recover from the disease after the appearance of the clinical symptoms.

(A) few people are known to recover from the disease after the appearance of the clinical symptoms

(B) few people are known to have recovered from the disease once the clinical symptoms have appeared

(C) there are few known people who have recovered from the disease once the clinical symptoms have appeared

(D) after the clinical symptoms appear, there are few known people who have recovered from the disease

(E) recovery from the disease is known for only a few people after the clinical symptoms appear

请问A错在哪里？这道题目在大全分类中找不到，谢谢

不定式的完成时表示动作发生在主句动作之前，因为肯定是recover这件事情先发生，后来才有know，所以用完成时表示两个动作的时间顺序。

个人浅见，仅供参考