1 as for：至于，关于

e.g As for the cost, that will be very little.

至于费用，那将是徽不足道的。

2 be sad about：因......而伤心，难受

e.g. I am pretty sad about not going.

不能去让我感到很伤心。

3 in a moment：立刻，马上

e.g. He has turned me sick in a moment.

他一下子就把我搞得六神无主了。