The missing children haven’t been found yet. Something terrible ________ to them.
_____ the night, we did nothing but _____ there, waiting for him to come.
_____ your help, we _____ complete the work in time.
I have a letter _____ to tell the headmaster that we need a room _____.
The house with the ground is valued ____ three thousand yuan, but I bought it ____ only one thousand yuan.
—Does David often come to school ____ bus? —Yes, but sometimes he comes ____ his father’s car.