VOA一分钟英语：过去完成时怎么用？

“时态（tense）” 是英语语法中的一大难点。尤其是当一个句子中存在不同时态的时候，要想准确地把握句意，就需要理解每个时态的具体用法。我们用过去完成时谈论过去某个时间点之前已经发生的事情。过去完成时的结构是什么？当一句话中，过去完成时和过去时同时出现时，哪一个时态所描述的动作先发生？
 
Hi, everyone, I’m James and today we’re going to talk about the past perfect tense – how we form it, and why we use it!
“By the time I arrived at the airport, the plane had already left.”
In this example, ‘had left’ is the past perfect tense. The structure for the past perfect tense is ‘had’ plus a past participle.
There are two past actions – ‘arriving at the airport’ and ‘the plane leaving’. But which of these happened first?
The clue is the past perfect tense! The action in the past perfect is the action that always happens first.
Because the verb ‘leave’ is in the past perfect, ‘had left’, we know that this action happened first.
The action that happens second is often in the past simple tense.
In this example: I arrived.
When you want to talk about two past actions, one which happened before the other, remember to use the past perfect for the first action, and the past simple for the second.
Thanks for joining us for this English In A Minute!
 
用法总结
1 过去完成时的结构是 “had” + 动词过去分词。
 
2 当一句话中有两个在过去不同时段发生的动作时，先发生的动作使用过去完成时，而后发生的动作则常用一般过去时。
By the time I arrived at the airport, the plane had already left.