楼主的第一个问题:一个句子前后是可以使用同一个时态的,这表示前后两个动作同时发生或者可以没有时间的分别.
第二个问题:
1.首先要清楚,have的时态,现在时:have.过去分词:had.
2.现在完成时的表示:表肯定:has/have+动词过去分词 表否定:has/have+not +动词过去分词
3.句中have not had 是现在完成时.其实后半句有一个词组:have an/any effect (on)意思是有影响.”but these have not had any effect“中的“had"就是have an/any effect on中的have,只不过用了过去分词形式,也就是 have not had any effect它的结构其实就是:have+not+had any effect(现在完成时的否定)
所以楼主不能单单拆下“not had any "来分析.
例句:Smoking has had a bad effect on health (我自己造句的,希望楼楼别介意,\(≧▽≦)/~)
意思是:吸烟对健康有着不良影响(就是我们常说的:吸烟有害健康)
but these has not had any effect
but these has not had any effect
Jasper has put up 'No Parking' signs outside his gate,but these have not had any effect.在这句话中,为什么前后都是完成时?后半句not had any 这个怎么理解?为什么还有一个had?
Jasper has put up 'No Parking' signs outside his gate,but these have not had any effect.在这句话中,为什么前后都是完成时?后半句not had any 这个怎么理解?为什么还有一个had?
英语人气:108 ℃时间:2020-06-03 21:05:29
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