If the phone_______wrong, you will get a new one for free or get all your money back.

10 years ago， _________ only one classroom building in our school. And in 10 years， _________ five classroom buildings in our school.

You have finished writing an e-mail on computer , but too many mistakes in it . You can click _____ .

_____ do you go back to your hometown? — Twice a year. [ ]

Why are there a lot of dead fish in the river?－Because they were ______ by the polluted water.