These doctors are busy day and night, a cure for AIDS.
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 ______.
When the clock __________ twelve o’clock, Cinderella suddenly remembered her godmother’s words and rushed away from the prince.
----Look! Where are you going? ---Sorry. I _______________.