________ hard one may work, one cannot master a foreign language in a month or two. 

It was clear that the speaker now trusted Dantes from the way _____ these words were said.

The single most important factor ____ contributes to success is _____ you do every single day．

．_____ we can pass the coming examination will mainly depend on _____ we learn and _____ learn it.

I try to understand __________ that prevents so many Chinese from being as happy as one might expect.