The young doctor is determined to devote all his life to ________ the cause of cancer.

He didn’t go there yesterday, _______he

Andy lives on the 10th floor. While his Uncle Jim lives 5 floors __________ in the same building.

The research on the new flu virus vaccine is challenging and demanding. Who do you think can do the job?—______ my students have a try?

．—-Why is the university doing so much building?—-______number of students______so rapidly