题目内容
13.______ for years,life on other planets is still a mystery for human beings.( )A. | Having been looked | B. | Having been looking | ||
C. | Having looked | D. | Looked |
分析 (尽管)已经找了很多年,外星生命对人类而言仍然是个谜.
解答 答案:A
题干中look for和主语life构成动宾关系,要用被动;句中有for years多年,是表达动作持续的时间,是完成时态的时间状语.故选A.
点评 现在分词是非谓语动词的一种,表达主动或进行;过去分词表达被动或完成;动词不定式表达未发生的动作.学习时,要注意区分和掌握.
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