释义：

not know the first thing about 对……一无所知

这是强调“对某事一无所知”的表达。about 后面接上要表达的事实就可以了。相似的句型有 not know the half of，not know a thing about 等。只不过 know a thing or two about 表示“对某事非常了解”。

例句：

I don't know the first thing about how to use it.
我完全不知道这个东西的使用方法。
You don't know the half of it.
你根本就不知道事态有多么严重。
I know a thing or two about playing computer games.
我非常了解电脑游戏。

对话：

A: Mary needs help with her computer.
玛丽的电脑坏了，需要帮助。
B: I don't know the first thing about computers.
我对电脑一无所知。