Mr. and Mrs. Green were going on their vacation with their children, and they had to arrive at the airport before 11:40 the next morning. “It takes us thirty minutes to get there in a car,” Mr. Green said, “so we must get ready before eleven o'clock. Don't be late.”
At ten fifty, all of them were busy doing something, but Mrs. Green wasn't. She sat quietly in a chair in the garden and enjoyed the good weather.
Mr. Green and the children were surprised, but Mrs. Green said, “Don't worry! Before I went to bed last night. I made all our clocks and watches twenty minutes ahead(提前). Now we can get to the airport early.”
Why did the Greens have to be ready before eleven o'clock?

A．Because they were going to a party.

B．Because they didn't go to the airport.

C．Because they had to go to the airport by bus.

D．Because they must arrive at the airport before 11:40.

How long does it take from Mr. Green's house to the airport by car?

A．Thirty minutes.	B．Twenty minutes.
C．Fifty minutes.	D．Forty minutes.

How did Mr. Green and the children feel when they saw Mrs. Green sitting in the garden.

A．They felt sad.	B．They felt happy
C．They felt surprised	D．They felt interested.

Why did Mrs. Green sit quietly?

A．Because she was sick.

B．Because she didn't like to spend her vacation.

C．Because she wanted to stay at home.

D．Because she made all the clocks and watches ahead and they wouldn't be late.

What time was it when Mr. Green and the children were busy doing things?

A．It was ten fifty.	B．It was eleven ten.
C．It was ten thirty.	D．It was eleven forty.