Someone's sister-in-law is the woman who is married to their brother.

一个人的嫂子是是嫁给他哥哥的女人

My sister-in-law is pregnant.

我嫂嫂怀孕了。

Then my sister-in-law asked the dreaded question.

然后我弟媳开口问了那个可怕的问题。

He delegated his power of attorney to his sister-in-law.

他把他的代理人的权力委托给他的嫂子。

It is hard to believe that I now have a sister-in-law.

很难相信现在自己有了个弟媳。

I didn't care for Wallis either, but she was not my sister-in-law.

我也不在乎沃利斯，可她不是我的嫂子啊！