E-mail, as well as telephones, ____an important part in daily communication.

Whatdo you do when it _____ —I often stay at home and read books.

I often see lights in that empty house. Do you think I _____ report it to the police? [ ]

Mr. Su _____ in Zhuyuan Middle School since1998. He regards it his second home.

Much to our relief, although we are not that rich, our income is now double______it was five years ago.