What about your study–I found ______ very difficult ______ all the subjects well.

He stared at the empty bottle for a while, feeling happy that he had sent the butterfly back ________ it belonged-nature[ ]

As far as I know, our manager has already had the matter ________， which we can know from his relaxed expression.

She was often late for school, ___ made her teacher very angry.

It is not profitable to provide bus services in districts where the population is widely _____.