1. To know everything is to know nothing.

样样皆通，样样稀松。

2. As if you didn't know.

明知故问。

3. You never know.

谁也说不准。

4. You can ask Jack for help, he knows the business.

你可以找杰克帮忙，他比较在行。

5. Scientists say that monkeys also know right from wrong.

科学家说猴子也能辨别对错。

6. They are almost totally dependent on Western know-how.

他们几乎完全依赖西方技术。

7. I know a little French.

我懂一点点法语。

8. This is a well-known brand in China.

这个牌子在中国很知名。