By the time they reached the bus stop, the bus__________ for ten minutes.

Thank you for the great effort you _____ to find us the right person for the job．

How can I get good grades in exams — The ___ careful you are, the ___ mistakes you will make.

The research on the new flu virus vaccine ischallenging and demanding Who do you think can do the job —_______ my students have a try

_________you have a rich knowledge of Chinese history, try acting as a guide for these foreign visitors