With the help of high technology, more and more substances _________ in the past
题型:不详难度:来源:
With the help of high technology, more and more substances _________ in the past years.A.discovered | B.have discovered | C.had been discovered | D.have been discovered |
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答案
D |
解析
试题分析:考查时态和语态。本题的关键是时间状语in the past years,该时间状语通常与现在完成时连用。既要:在高科技的帮助之下,在过去几年里越来越多的物质被发现了。根据惊句意说明使用被动语态的形式。故D正确。 点评:时态题的考查关键是抓住句子的上下文含义和句中的时间状语。要根据时间状语来选择合适的时态,在平时的学习中要注意积累有关时态的用法和各种时态的特殊之处。如since, so far等经常与现在完成时连用。在条件状语从句中用一般现在时代替将来时等等。 |
举一反三
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