---Are you going to Shanghai by train?---No. I’m taking car.
| A．/;a | B．a; the | C．/; / | D．the; a |
John didn’t go to bed ______he finished his homework.
A.until B.after C.while
It took him half an hour _____ the work.
A.doingB.to do C.did
The teachers are very friendly ______their students.
A.to B.at C.on
His shoes are ___dirty ____he has to wash them .
A.too, to B.so, that C.enough, that
She missed the bus,_____she had to walk home.
A.so B.but C.because