1 think we'd better keep to the subject, we'11 waste our time.
All the students are looking forward to the first ________to take the College Entrance Examinations.
Bob would have helped us yesterday, but he-_______
George is going to talk about the geography of his country, but I’d rather he_______ more on its culture.
Fever is a ________of many illnesses. So I suggest you take it seriously and see a doctor as soon as possible.
Had I known about this computer program, a huge amount of time and energy .