Schools in the north tend to be better equipped, ______ those in the south are relatively poor.
His sister left home in 1998,and ________ since.
In the near future,more advances in the robot technology ________ by scientists.(2011·湖南)
John, a friend of mine, who got married only last week, spent $3,000 more than he ________ for the wedding.
—Hurry up!Alice and Sue are waiting for you at the school gate.—Oh!I thought they ________ without me.
We arrived at work in the morning and found that somebody ________ into the office during the night.(2011·江西)