You look so tired. You _____have stayed up late again. [ ]

Who will send you to the new school, your mom, your dad or your uncle— _______. I’ll go there by myself.

The Canadian tourist hurried to the station, only _____ that the train had pulled out of the station.[ ]

The employees were asked to concentrate their attention________improving the quality of the products.[ ]

The 16th Asian Games ____in Guangzhou from November 12 to November 27，2010