1. know of 知道,听说
I know of her but I have never met her.
我知道她但和她不相识
。2. be in demand 供不应求
You may know that nurses are in demand, but what about the folks they work with?
你可能知道目前护士就业形势很好,但是医疗技师是做什么的呢?
3. be better off 富裕,状况好
For example, have you ever wanted something that you couldn’t get but then tell yourself you’re better off without it?
举个例子,你曾经有没有想要某些东西但是你又得不到它,所以你就自己安慰自己说没有那个东西你反而更好呢?
4. invest in 投资于
We have to invest in science for ourselves.
我们需要为我们自己而投资科学
。