—Sandy,is Mr Li in the teachers' office now?
—I am not sure.He ______ be there.
A.mustB.can'tC.mustn'tD.may
It's necessary for students ______with their teachers.( )
A.communicateB.communicating
C.to communicate
It's time for I'm a Singer,please ______ the TV.( )
A.turn onB.turn offC.open
Yu Gong kept moving the mountains,______ he was very old.( )
A.soB.althoughC.but
We ______ the tea set for three years.( )
A.have hadB.hadC.have been
The sweater ______ belong to Jim.It's much too large for him.( )
A.mustn'tB.can'tC.needn't