A girl on the bus begin to sing a pop song and soon all the other students _________.

_____improve her English, Jenny bought a lot of tapes for herself.

Development of science and technology must benefit people ______ harm them.     

____ the consequences of the chemical leaks, the specialists haven’t given final conclusion before they obtain accurate statistics.

China has been pushing the reform of public hospitals ______ all its citizens.

—Do you like working as a waiter?
—Yes, but I get tired ______ standing the whole day．

My interests include football, bowling and surfing the web ______ studying my favorite subjects．

I cannot______ puzzled, for I simply cannot understand how I could have made such a stupid mistake.

I feel sure that ________ qualification， ability and experience，you are the most qualified one to do the job.

Some scientists think there are _______ 2，000 million flashes of lightning per year.