The government ______ air quality in urban areas from levels one to five: excellent, fairly good, slightly polluted, poor and dangerous.

I can't leave.She told me that I ________ stay here until she comes back.

I don’t doubt ______ for the journey by doing jobs on the ship.

If you can't________ your shyness, you’ll never pass the interview.

 Even after I ______ to soil science, I sometimes wondered whether 1 was doing what I wanted to do.