The roof fell ____ he had time to rush out.
John says that his present job does not provide him with enough _____ for his organizing ability.
_____, I couldn’t find a solution to the problem.
The meeting was _____ when the chairman fell ill.
The members of the club wouldn't run a _____ in entrusting(委托) the organization to an unreliable person.
Many new _____ will be opened up in the future for those with a university education.