The warranty(保修) on these phones is oneyear_____I am covered if it broken?— That’s right_____ it’s damaged.[ ]

I found the naughty boy _____behind the door to frighten his sister [ ]

How nice you are! You always do what you can ____________ others.

Great changes_____ in the small city in the last 20 years

There is ____”U” and _____”S” in the word “use”.