The new generation of computers, with artificial intelligence, _______and perfected now.

The new dictionaries are very useful. They _______ well and _______ already.

With more forests being destroyed in that area, huge quantities of land _______ deserts each year.

The first few years in the 21st century ______ the rapid rise of China as a world economic power.

She told me that she would not go with us if it ____ the next day.

----My car broke down yesterday on the way to the Yue Lu mountain.
----I am sorry to hear that, but you _______that car every day for ten years before it broke down. Now you really need to buy a new one.
A. have used      B. have been used    C. had used     D had been used

---- What were you doing when Tony phoned you?
---- I had just finished my work and _____to take a shower.

----The train will arrive at the station in half an hour. Who ______for us? 
----I am sure Dad will be standing there when we get off the train.

Although medical science________ control over several dangerous diseases, what worries us is that some of them are returning.?

—You seem to be familiar with this city．
—I       here for three years．It's great to be back．