“What’s going on there?” “Sorry, I don’t know what ___”
Sir, you ________ be sitting in this waiting room. It is for women and children only.
The train has gone. You two ________ on time.
There was plenty of time. She ________ to the station.
Some pirates(海盗)appeared, so they ________ change their route.
—Must all the passengers in the airbus be foung now? —No, they ________, because none of them is affected by the flu.