For example, present becomes past, and past becomes past perfect.

比如，现在时变成时，时变成成时。

With this grammar, you're going to use the past perfect.

有了这个语法，你就会使成时。

They're not expecting you to use all past perfect because that just wouldn't make sense and it wouldn't make for a readable essay.

他们没有期待你都是成时，因为这样说不通，而且无法写出一篇论文。

I had never been to, okay, past perfect.

I had never been to，成时。

And instead of using past perfect forms he uses past simple forms.

这里，他没有成时而是了一般时。

That's an example of the past perfect.

" had departed" 就是成时。

This is the present perfect continuous, the past perfect uses had.

这是现在成进行时，成时使是 had。

But the last questions can be conditionals present or past perfect.

但最后一个问题以是条件句现在成时或成时。

And finally, the conditional perfect continuous; I would have been eating chocolate.

最后是成进行条件句（将来成进行时）；我会一直吃巧克力。

Mistake number five, past simple or present perfect.

第五类错误，一般时还是现在成时。

In this sentence, had forgotten is the past perfect tense.

在这个句子中，had forgotten 是成时。

It was past perfect and the verb was " had studied."

它是成时，动词是 had studied。

However, in spoken English, Americans sometimes use the simple past instead, like this: " I wish I studied harder for the entrance exam" .

但是，在英语口语中，美国人有时会一般时而不是成时，例如：" 我当初要是努力准备入学考试就好了。"

You can also use if only plus the past perfect, like this: If only I'd kept my Spanish going.

你也以 if only 加上成时，像这样：要是我能继续学西班牙语就好了。

But while we wait for Pete, let's talk about a new verb tense: Past Perfect.

但是在我们等皮特时候，我们来谈谈一个新时态：成时。

The perfect tenses by which I mean the present perfect and the past perfect tenses are quite challenging.

我指是现在成时和成时成时态是相当具有挑战性。

And past perfect, I was able to add it in.

然后是成时，我能够加入它。

Again, specific details: past simple or past continuous; general experiences until now: present perfect.

再次强调，具体细节：一般时或成时；直到现在一般经历：现在成时。

When you are talking about regrets about the past, you can use WISH with the past perfect.

当你谈论对遗憾时，以 WISH+成时。

If something didn't happen and you want to be specific, use the past perfect form of 'hope'.

如果某事没有发生，而你又想说得具体些，以 hope 成时。