to forget is a good way to solve our problems and we can also deal with them by of some

问题补充：

to forget is a good way to solve our problems and we can also deal with them by of something worse.

A. Learn; think

B. Learning; think

C. Learning; thinking

D. Learn; thinking

答案：

A. Learn; think

B. Learning; think

(答案→)C. Learning; thinking

D. Learn; thinking

解析：句意：学会忘记是解决问题的好方法，我们也可以通过思考更坏的情况来处理。前面的一个动词作主语故用动名词，后一动词跟在介词by之后故也用动名词。所以选C。