-Why are you so familiar with my close friend Nipple？

-Yeah，I happened，believe it or not，___him in a packed trip.

A.to meet B.to be meeting C.to have meet D.to be meet

答案是C，但是A为什么不能选啊，我认为这明明是过去发生的一个动作。

就语法而言，happened to meet 和 happened to have met 都对，都表示“在过去碰巧遇见了他”。

但是，这两个还是有区别的。前者只描述当时的情况，后者描述某事的原因，即：为何与我的朋友熟悉，因为原因总是在先的。

我设置两个语境：

I happened to meet Mary when I was taking a walk.

I know the story very well because I happened to have seen the film.

以上两句都是指“碰巧做了某事”。

（第二句 to have seen 跟 happened 无关，不是发生在 happened 之前，而是跟 know 相比较，早于 know）

黎老师这个说法不对吧：

不定式的动作（遇见）在谓语动词happen之前发生。

to have met  跟 happened 无关，完成体不是指发生在 happened 之前，而是在另一个动作之前。这也充分证明了 happened to 的半助动词特征。

-why are you so familiar with my close friend Nipple？ -Yeah，i happen，believe it or not，___him in a packed trip. A.to meet B.to be meeting C.to have meet D.to be meet 答案是C，但是A为什么不能选啊，我认为这明明是过去发生的一个动作

【答】 A.to meet 是动词不定式的一般式， C.to have meet 是动词不定式的完成式。如果不定式的动作在句中谓语动词动作之前发生，就要用不定式的完成式。在本句中，不定式的动作（遇见）在谓语动词happen之前发生，所以答案 C 是正确的，而 A 是错误的。

-why are you so familiar with my close friend Nipple？

-Yeah，I happen，believe it or not，___him in a packed trip.

答话人用一般现在时happen是没有问题的。由于谓语为现在时，而meet him是过去的事，所以不定式用完成体。

如果谓语用一般过去时happened，则后接to do不定式一般体。

COCA预料库有很多happen to have done sth的例句。

I happen to have found quite a bit of value in Melissa and Evelyn's blogs.

Now I happen to have spent 18 years as a trader and I hated it, okay.

I happen to have gotten the flexi-disc in a comic book with Ty Templeton's Right to the Blues on the flip side. 

The only resistance I've ever seen against this principle has been from machine builders and system integrators who like to push their favoured suppliers because they get a better discount from them or because they happen to have spent a lot of money on programming software from that vendor.

You happen to have given me a great example of a behavior...

I just happen to have used my Google identity when I first posted a comment here.