He has some doubt ________ he will succeed in his research work.
You can’t imagine the difficulty he _____ onto the cliff and saving the boy in trouble.
_____ this house with that one, you’ll find this house is better.
Our bodies are strengthened by taking exercise. ______, our minds are developed by learning.
The whole village was _____ by the rainstorm.
--- I’m sure Andrew will win the first prize in the final. --- I think so. He _____ for it for months.