3．
If you watch the sky about an hour after the sun goes down，you may see some"moving stars"．But they aren't real stars．They're satellites，a machine that has been sent into space and goes around the Earth，moon，etc．And the biggest of all is the International Space Station （ISS）．
The ISS is the biggest satellite because scientists want to live on it．They think that the best way to learn more about space is to live there．The space shuttle Discovery has taken off from the Kennedy Space Center in Cape Canaveral，Florida several times and carried a few groups of astronauts to the International Space Station．
When the space station is finished，it will be like a city in space．People will stay and study there with many of the things they have at home．Laboratories，living rooms and power stations are being built．The ISS is the most expensive space program ever．Millions and millions of dollars are being spent on it every year．
Scientists hope that the ISS will be a stepping stone for future space exploration．"The ISS will help us better understand the human body，explore （know more about） space and study the earth．It can help us make life on the earth better，"said Kathryn Clark，an ISS scientist．
Sixteen countries are in the program：The US，Russia，Canada，Japan，Brazil and 11European countries．China is not an ISS country，but it has helped with some of the experiments．In 2003，China sent some rice up to the ISS to find out what space would do to it．
Twenty Chinese students talked directly to an astronaut （spaceman） in the International Space Station （ISS） on radio in Nanjing，capital of east China's Jiangsu Province on Sunday，2007．The 20students，aged 10to 19from Shanghai，Guangzhou and Nanjing，began talking to Clayton C．Anderson，a 48-year-old American astronaut at 18：50p．m．at Nanjing No.3Middle School when the ISS was passing over Nanjing．
After it's finished，more than 90percnt of the world's population will be able to see the space station．So keep looking up，and maybe you'll see it get bigger and brighter．
55．It seems thatA．
A．we can probably see the ISS when the sun goes down
B．some students from Nanjing have been to the ISS
C．China is one of the members in the ISS group
D．the ISS is still in the space but has stopped working
56．"Power stations"in the third paragraph infersC．
A．houses for people to live in，to study and do research work
B．machines that go around the earth，the moon and some stars
C．buildings where electricity is produced to supply a large area
D．some countries which help send the ISS up into space
57．---Why did the scientists send up the International Space Station （ISS）？
---Because theyD．
A．would send up most of the earth people to live there
B．could talk with some Chinese school students
C．hoped to travel to Mars and Venus some day
D．wanted to live in space and do better research．
