I was goofing around and broke my arm.

我在四处闲荡时摔折。

Lew and I started goofing on Alison's friend.

我和卢开始嘲笑艾丽森朋友。

We just goofed around till the train time.

在火车开车前我们只是闲荡一阵。

You'd goof things up good.

你会把事情完全搞糟。