It was ______ back home after the experiment.
Cleaning women in big cities usually get ____by the hour.
It is about time that he ______ to supper, for he still has a meeting to attend this evening. A goes B went C has gone D go
Only when class began ______that he had left his book at home.
They will fly to Washington, ______they plan to stay for two or three days.
The explanation of our teacher will make the reading easy ______.