Only by practising constantly greater progress. A. we can makeB. then we will makeC. can w

问题补充：

Only by practising constantly greater progress.

A. we can make

B. then we will make

C. can we make

D. we must make

答案：

A. we can make

B. then we will make

(答案→)C. can we make

D. we must make

解析：考察主谓倒装。当only位于句首引导条件从句时，主句部分倒装，从句不倒装，只有选选项C为倒装语序。故选C。