The teacher asked the students to           a story about a trip to the moon.

When we heard the good news , all of us were very ______ .

—Chinese people are worried about the food they eat these days.—Yes, the food safety is a serious         in our country. We should try to solve it.

 –__________is your cat?– The black one on the floor.

—Excuse me, is this your iPad ?          —No, it isn't.             is at home.