before是完成时态的标志吗（before与完成时态连用解析）

1.与现在完成时态连用，表示“从现在开始追溯到过去的一段时间”，如：

I think we've met before.

我觉得我们以前见过面。

My brother has never been abroad before.

我的哥哥以前没有去过国外。

I've been here before.

我以前来过这儿。

Have you ever used this software before?

你以前用过这种软件吗？

Have you heard about it before?

你过去听说过这件事吗？

I have never met him before.

我以前从未见过他。

I’ve never heard that word before.

我以前从没有听过那个词。

2.与过去完成时连用，表示“从过去的一个时间点算起的以前”，如：

The war had ended only a month or so before.

战争大约一个月前才刚刚结束。

It had been fine the week before (= the previous week) .

前一个星期天气很好。

That had happened long before (= a long time earlier) .

那是很早以前的事了。

He said that he had met the man somewhere before.

他说他以前在什么地方见过这个人。

Several weeks had gone by before I realized the painting was missing.

几周之后，我才意识到那幅画丢了。

We went to that movie a few nights ago. We hadn’t gone to that before.

几天前的晚上我们去了那家电影院。以前我们没有去过那家电影院。