__________ his project, the boy had to stay up late.
This problem may lead to more serious ones if ______ unsolved.
Many Chinese universities provide scholarships for students _______ financial aid.
E-mail, as well as telephones, ______ an important part in daily communication.
_____ would be more convenient to place the toilets near the entrance to the cinema for disabled customers.
—I’m terribly sorry that I made your clothes dirty.—__________.