I can’t ______ it in English because I can’t _____ English. Can I ______ you the story in Chinese

It is strange that the small boy _________ work out such a difficult exercise, which is even hard to settle for adults.

The old man _______all his money to a charity.He is really great .

_______ with so much trouble，we failed to complete the task on time.

One of my_________ is clean, but_________ one isn’t.