— How is your English study?Not bad. But I learning English grammar.A. am interested in B.

问题补充：

— How is your English study?

Not bad. But I learning English grammar.

A. am interested in

B. am good at

C. have a little trouble

D. have no trouble

答案：

A. am interested in

B. am good at

(答案→)C. have a little trouble

D. have no trouble

解析：考查固定短语的用法。have trouble doing sth.意为“做某事遇到了困难”；答语说“还不错。但是……”，由这个转折词可以看出说话人在语法学习上遇到了一定的麻烦，故答案选C。