15.21.Why do many people like to travel by plane?
A.Because it is fast.
B.Because it is safe.
C.Because it is expensive.
22.Which is not the good thing about the train?A
A.It takes more time.
B.You can walk around in it.
C.You can open the windows.
23.If Jack wants to carry a lot of things with him,what does he probably take to go out?
A.A plane.
B.A train.
C.A car.
24.What is the bad thing about the car?
A.you needn't go to a station
B.you can start your journey when you want to.
C.There are too many cars on the road.
25.Which of the following is true?
A.Jack likes to take a train because it takes more time.
B.Jack thinks an airport is usually far from a city.
C.Jack likes to take a car because it's fast.