题目内容
18.Silk ______ one of the primary goods traded along the Silk Road by about 100BC.( )A. | had become | B. | was becoming | C. | has become | D. | is becoming |
分析 到大约公元前100年为止,丝绸已经成为丝绸之路上交易的主要商品之一.
解答 答案:A
句中的时间状语"by about 100BC"意为:到大约公元前100年为止,大约公元前100年之前;表示在过去之前;所以此处应使用过去完成时即had+动词的过去分词形式;
B.was becoming过去进行时,表示在过去某一时刻或某一段时间内进行或发生的动作,不强调是否完成;C.has become 现在完成时,表示过去发生的动作对现在造成的影响或结果,动作发生的时间是过去;D.is becoming现在进行时,表示现在正在发生的动作或存在的状态;因此B.C.D都不合句意;故选A
点评 本题考查了过去完成时的用法:即表示过去某一时间或动作以前已经发生或完成了的动作,该动作发生的时间通常是在"过去的过去";它的时间状语可以是由by,before等构成的短语;其中by意为:在…之前,到…为止;因此做该题的关键是看它的时间状语是否表示过去的过去;另外,还要注意总结它与现在完成时以及过去进行时的区别.
练习册系列答案
相关题目
13.I'm going to _____ advantage of this tour to explore the history of the castle.( )
A. | put | B. | make | C. | take | D. | give |
12.The adoption of orphans and physically challenged children has been a subject of public debate _______ a fire in an unregistered orphanage last month.
A. | according to | B. | in case of | C. | ever since | D. | such as |
13.The news came as no surprise to me.I ______ for some time that the factory was going to shut down.( )
A. | knew | B. | had known | C. | have known | D. | know |