Mr. Green didn’t understand ________ made his daughter so absent-minded this morning.

Math is too difficult. I want to give it up. —Please don’t. Nothing is _________if you put your heart into it.

The window of my bedroom is ______ the door. [ ]

_____ made our school proud was _____ more than 90% of the students had been admitted to key universities.

We’ll be back for our school’s _____ anniversary ceremony(周年庆典). –I see. That means you’ll have a get-together with your classmates in ___ years.