I will lend you the money ____ you pay it back in one month.

What are you going to do this weekend?—–I’m going to help _____the city parks with my classmates to make them clean.

As students, we are supposed to spend more time _________ .

You’ve read the Frog by Moyan , haven’t you?—Yes, I_______ second time and I got a better understanding.

It’s only when you lost something __how much you value it.