, I think, and the problem could be settled.
A. So long as you keep up your spirits
B. A bit more effort
C. If you doubt your efforts
D. Making great efforts
网友回答
A. So long as you keep up your spirits
(答案→)B. A bit more effort
C. If you doubt your efforts
D. Making great efforts
解析：考查固定句型：名词短语+and/or+简单句，句意是：再多点努力，问题就解决了，其他几个选项都是状语，和并列连词and不符。选B。