He used to _______ in a village, but now he has been used to _______ in the big city.

I am fond of my sister but she has one serious shortcoming. She _________ be really stubborn.

—What does the sign over there read?—No person        smoke or carry a lighted cigarette, cigar or pipe in this area.

—Why can your neighbor know so much about London?—He ____ have been there before.

－Who’s that girl swimming in the pool? Is it Lucy?－It        be Lucy. She is sleeping in her bedroom now.