Now China is fighting against illegal cooking oil（地沟油）, a kind of waste oil _____can cause a lot of illness.

It’sdifficult for such a girl to swim ____ the river.

Who were potato chips invented by

Haven’t I told you that the computer needs______—Sorry,I forgot_______it fixed.I’ll send it forrepairs right away.

The remarkable shift ________ young people’s job preference in recent years has analysts and educators greatly concerned