Nearly half a million people are believed their homes in the past months as a result of t

问题补充：

Nearly half a million people are believed their homes in the past months as a result of the disaster.

A. to leave

B. to have left

C. to be leaving

D. to be left

答案：

A. to leave

(答案→)B. to have left

C. to be leaving

D. to be left

解析：

试题分析:考查非谓语的用法。句意：人们相信几乎有50万人在过去的数个月中由于灾难的原因而离开了家园。在句型sb /sth +is said to do 中，如果不定式动作发生过了，则用不定式的完成式to have done表示；如果将要发生，则用不定式的一般式to do表示；如果不定式动作正在发生，则用不定式的进行式to be doing表示。在此句中 in the past months 提示动作已经发生，则应该用不定式的完成式。所以B选项正确。