—What do you think of teaching,Bob?—I find it fun and challenging.It is a job ________ you are doing something serious but interesting.
The International Maths Summer Camp was held in Wuhan,____ the top students in maths from all over the world.
The meat tastes as though it ____ bad. Throw it off.
The manager always put ____ of his workers before__________.
Not until ____ finished my homework ___ to watch TV.
Today Xiao Li is absent ___the class. He ___ ill.