Rather than _____on a crowed bus, I prefer ____to work every day.
Mike, whose ambition is to become a network engineer, was always ______from other boys by his programming ability.
Harry telephoned to the airport to______ whether Flight 24 for San Francisco is departing on time.
—Will you be ______ this evening, Mary?—That depends. I am afraid I will be with my manager discussing a plan.
Children who are spoiled by their parents are more _____ than others —they are more likely to fight with their fellows for toys and candies.
Some people say that Mars should be protected as a wildlife reserve where we do everything possible to avoid pollution, on the _______ that life could exist on it.