Though most people know that smoking ________ the risk of cancer,it is still hard for them to give it up.[ ]

I won’t leave my office until my work.

Examtakers’ “virtue” will be taken into ________ in the future nationwide public servants’ exam.

It will be at least three weeks________ he recovers from his illness and returns to work

It was early morning in London _____ Prime Minister Cameron arrived to give his speech.