An odd thing happened to me on my way to the office last week.上周我在上班的路上遇到一件怪事。

I wonder what/whatever happened to that guy. [=I wonder where that guy has gone and what he has been doing]我想知道那个人怎么样了。

I promise nothing will happen to you.我保证你不会有事。

What happened to the car? There's a big scratch on the fender.车怎么了？挡泥板上有一道大划痕。