--Where is Mother? ---She is in the kitchen. She ______ the housework all morning.
I could just see a car in the distance, but I couldn’t _____ what color it was.
What did you ____ me ____? I’m a teacher, not a doctor.
The new discovery is of ________.
Once _____ , the machine will keep running.
____ in thought, he almost ran into the car in front him.