Peter ________ at this job since he graduated from college.
I’m very grateful to my high school teachers, without ______ help I wouldn’t be so excellent.
I ______ for Shanghai this Saturday, so I want to know when the earliest plane ______.
He ______ it on schedule, but somehow he fell behind.
The doctor’s dilemma was _____ he should tell the patient the truth.
All we have is 24 precious hours a day and therefore we shall waste ______