Beijing isn't what it used to be. The last decade ________(witness) great changes in the city images.

A survey of China's citizens found that some smokers are unwilling to kick the habit because they aren't fully aware ________ the harm it does to health.

I have urged Tony ________(stay) away from computer games before he becomes addicted to them.

The boss refused to sell the car for ________ he thought was not satisfactory.

—Do you work in this office?

—No, as a clerk in this office is on vacation, I'm just helping______ here for about a week.

We are now enjoying the cool air in the room. ________ the meantime, the farmers are harvesting crops in the hot sun.

—Jack, this is the third time that you have been late this week.

—Sorry, sir, but I was help ________ for 15 minutes on the way here in the traffic jam.

—Look, the absent?minded student is holding the book upside________.

—He is much too careless.

Jane lay on the floor ________(tremble), too ________(scare) to move.

If he fails again, he will drag us all ________ with him.