'Congratulations!' he said, slapping me on the back.

“祝贺你！”他拍着我的背说。

《牛津词典》

He had a paw on my throat, and with the other, he was slapping me!

他一手掐住我的脖子一手来回扇我巴掌！

youdao

And I don't know what made me do this, but I just started knee-slapping laughing, and I couldn't stop.

然后我当时自己都不知道我为什么这么做，我就开始放声大笑，笑得都不行了，停都停不下来。

youdao