Even though the radioactive isotope is considered relatively harmless, the region's fishermen, like its farmers, have been struggling for years to restore the reputation of...
3.基本结构:have/has + done 4.否定形式:have/has + not + done. 5.一般疑问句:have或has提前。 6.例句:I've written an article. It has been raining these days. 六、过去完成时 1.概念:以过去某个时间为标准,在此以前发生的动作或行为,或在过去某动作之前完成的行...
被动语态的结构为be动词加动词的过去分词,即“be+done”。在不同的时态中,be动词有不同的形式。 二、常用被动语态的情况 1.不知道动作的执行者是谁。 This watch is made in China.这块手表是中国制造的。 2.没有必要指出动作的执行者是谁。 Many trees must be plant...
注意:如果不定式中含有be, have,或have been,一般要保留be, have或have been。 -Are you on holiday?你放假了吗? -No, but I’d like to be (on holiday).没有。不过我真愿意。 -She hasn’t done it yet.她还没有做。 -She ought to (have done it).她该做。
1.should have done =ought to have done 本应该做而没做 2.would have done = 本来就会去做某事而没做 3.could have done = 本可以做某事而没做 4.might have done 本可以做而没做 例:They ought to have apologized. 他们本该道歉的。
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