"You do not need to be a rocket scientist." Americans hear these words often.People say them in schools，offices and factories.Broadcasters on radio and television often use them.
   How did the expression begin？No one seems to know it. （1）

G

G

"It grew，" he says."Because rocket scientists probably are the most intelligent people around."
   Not everyone would agree.（2）

F

F

For example，a person who speaks fifteen languages，or a medical doctor who operates on the brain.Still，many people would agree that there is something special about scientists who build rockets.Maybe it has something to do with the mystery of space travel.
   Moving pictures from before World War Ⅱ showed a man named Buck Rogers landing on the planet Mars.（3）

D

D

The rocket scientist is a different kind of jye.airo.He or she makes space travel possible.
   （4）

E

E

A Washington rocket scientist told about a launch that was put off many times.Finally，everything seemed right.Mechanical failures had been repaired.The weather was good.The scientists had planned that part of the rocket would fall into the ocean after the launch.All the ships and boats within many kilometers of the danger areas had been warned.But in the last few seconds a small boat entered the area. （5）

A

A

   When the work goes well，most rocket scientists enjoy their jobs.One scientist said，"As a child I loved to build the rockets.Now I am a grown-up.I still love to build rockets.And now I get paid for it."

A.Once again，the launch was put off.
B.Have you ever heard of the space travel？
C.It's dangerous for rocket scientists to build rockets.
D.He was a hero who could withdraw any enemy from outer space.
E.Rocket scientists，however，can have problems just like everyone else.
F.Some people might be considered more intelligent than rocket scientists.
G.But an official of the American space agency，NASA，says the expression just grew.