Question

Rare species in the world, ______ by hundreds every year, must be jointly preserved by all countries, or humans will encounter ecological disaster in the near future.

Answer 1

A. disappeared     B. disappearing     C. disappear        D.having disappearedB

试题分析：考查现在分词作状语。disappearing by hundreds every year做原因状语，disappearing的逻辑主语是Rare species，句意是在世界上，每年有上百种的珍稀动物消失，所以所有的国家必须联合起来保护它们，否则在不久的将来人们将遭遇生态上的灾难。Disappeared过去分词，表示已经完成的动作；having disappeared现在分词的完成式，表示谓语动词动作之前已经完成的动作；disappear动词作谓语，题干的谓语是must be，现在分词表示正在进行的动作，根据句意选B。
点评：现在分词的构成是动词原形加ing，被动语态是being done，完成式是having done，having been done。在句中可做表语，状语，定语，补语等。