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

比如，现在变过去，过去变过去。

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

有了这语法，你就会使用过去。

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用过去，因为这样说不通，而且无法写出篇可读的论文。

I had never been to, okay, past perfect.

I had never been to，过去。

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

这里，他没有用过去而是用了般过去。

That's an example of the past perfect.

" had departed" 就是过去。

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

这是现在进行，过去使用的是 had。

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

但最后题可以是条件句现在或过去。

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

最后是进行条件句（过去将来进行）；我会直吃巧克力。

Mistake number five, past simple or present perfect.

第五类错误，般过去还是现在。

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

在这句子中，had forgotten 是过去。

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

它是过去，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，美国人有会用般过去而不是过去，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.

你也可以用 if only 加上过去，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.

但是在我们等皮特的候，我们来谈谈新的态：过去。

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

我指的是现在和过去的态是相当具有挑战性的。

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

然后是过去，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：般过去或过去；直到现在的般经历：现在。

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

当你谈论对过去的遗憾，可以用 WISH+过去。

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，可以用 hope 的过去。