The old couple looked at the plane with their son on it until it was ______.

A. at the first sight B. out of sight

C. in sight D. at the sight of

I don’t care ____ or not you like the plan.

A. if B. whether C. that D. how

It is thought that Zheng He, a Chinese in the Ming Dynasty, may have been the first person who _____________America from the East.

A set out to B. set about to

C. set sail to D. set sail for

______ is said, the Yeti is a large, hairy animal that walks on two feet like a human being.

A. It B. That C. As D. What

We shall never forget the days ________ we spent playing happily together.

A. in which B. which C. when D. on which

The Sahara Desert is almost _____ of the US.

A. as big B. the size

C. the area D. the same

Though faced with so many difficulties, they are _____ about their future.

A. curious B. enthusiastic

C. optimistic D. concerned

There are _____ flights between the two cities, _____ it convenient for people in one city to travel to work in the other.

A. regular; to make B. usual; making

C. usual; having made D. regular, making

Police in America have stepped up their search for a fifteen-year-old boy who went _____ three days ago.

A. going B. losing

C. missing D. disappearing

-- You look so tired.

--- Yes. I _____ the house all the morning. But I’m finishing it soon.

A. have cleaned B. have been cleaning

C. have been cleaned D. had been cleaning