Human beings are always full of the spirit of discovery. Zhang Qian was an excellent official and explorer in Chinese history. He went on two (trip) to the Western regions. He opened up a very important route—the ancient Silk Road and (bring) back information. Besides, he introduced many things were seen for the first time. Zhang played a very important role in taking China to the world of commercial (商业的) trade. Christopher Columbus was an Italian navigator (航海家). (bear) in the 15th century, he (rise) to become a great navigator. At that time, many (Europe) countries became stronger and stronger. Their ships reached Africa and Asia. They got gold, silver, silk, tea and other things from the east. Columbus wanted to make another way to China and India. On 3rd August, 1492, Columbus left Spain and began his (one) voyage. After about two (month) hard sailing, he and his fleet got to an island in the Bahamas. On 28th October, they reached Cuba and he thought it was Asia. They went back to Spain on 15th March, 1493. Although they didn't get to the Orient or bring back wealth, they found a new place—the American Continents, which is also known the New World. From 1492 1504, he completed four voyages across the Atlantic Ocean. He reached most of the coast of South America and set up many colonies (殖民地).
Spacetravel is nothing new. The first spaceship with a human was sent up1spacein 1961. Since then, people have not only travelled to space,2manyof them have also lived there in space stations for some time.
The Soviet Union (苏联) sent the3space station into spacein 1971. This space station was called Salyut I. It4asa place where people could live while they observed space and did experiments.The first group of astronauts lived there for 23 days. The Soviet Union went onto make six more Salyut space stations. At about the same time, the UnitedStates had5own space station, called Skylab.
Astronauts6inthese space stations for a short time. However, it wasn't until the late 1980swhen the Soviet Union sent the Mir space station that people began to live inspace for a7time.
Living inspace stations seems to be fun, but astronauts face many problems. One of them8food.All the9on space stations are put together onEarth and sent there by space shuttle. Because the food has to last a longtime, a lot of it has to be stored in cans. The space station does not have afridge, but it has a cool room to keep fruit and vegetables fresh. Astronautsalso eat many other foods10dried meat that do not need specialcare.
