they had just had enough time to swim out of danger when the

来源：学生作业帮编辑：神马作文网作业帮分类：英语作业时间：2024/11/17 09:21:14

they had just had enough time to swim out of danger when the boat again completed a circle.
解释两个had 越清楚越好

had=have 的过去式和过去分词
首先,先弄清：
1,they had就等于是they have 的过去式
2,they have had等于 p.p(present participle现在分词)现在完成的用法
3.而在这个情况,they had had就是代表 past participle 过去分词（过去完成式）的用法.
2,3其实有点类似
那么来比较一下2,3的区别,they have just had enough time就是他们刚好有足够时间,而3呢就是在过去他们刚好有足够时间.
事实上意思都是指他们有足够时间.
那什么时候用呢,就是要看一个整体的了!一句句子,假如没有后面那句when the boat again completed a circle.那么这句句子其实是可以直接用present .p的.
然而在这个情况下,when the boat again completed a circle.已经是过去发生的事情,所以在过去发生的事情前提下,就不能用present.p现在分词了,就要用过去分词,意思就是when the boat again completed a circle.的时候刚好他们有足够时间游泳逃出危险!用past participle 来表达!也就是过去完成式
（p.s本人是读国际学校的,从小家庭学校说双语,我们都是直接会用grammar的,所以没有很懂那些所谓的什么谓语什么的一些专业名词,但我可以尽量用一个容易明白的方法来解释,希望楼主体谅哦!还有选我吧!我可是打了25分钟啊!）

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