You can come here to ask me if you have any questions.A. at one timeB. at a timeC. at any

You can come here to ask me if you have any questions.
A. at one time
B. at a time
C. at any time
D. all the time

A. at one timeB. at a time(答案→)C. at any timeD. all the time解析：考查短语辨析，at one time 一度，曾经，at a time 一次，每次，at any time 在任何时候，all the time 一直，句意：如果你有问题的话任何时候你可以过来问我。故选C。

这个答案应该是对的