问题
选择题
As we all know, Jack is experienced _____ the problem of this kind.
A．to work out
B．at working
C．at working out
D．for working out
答案
答案：C
考查短语be experienced at在某方面有经验。At是介词后面接名词或者动名词。句意：众所周知，杰克在解决这方面的的难题上有经验。Work out解决，算出，故选A。