BEING an astronaut sounds cool, doesn't it? In space, they get to do some pretty amazing things, like floating in zero gravity(重力).
However, there are also plenty of things that astronauts can't do because of their weightless environment, and that's very sad. What's worse, they can't even let their sadness show, because it's impossible to cry in zero gravity.
Of course, astronauts can still produce tears. But crying is much more difficult in space, according to The Atlantic(大西洋月刊) in January. Without gravity, tears don't flow(流动) down out of the eyes like they do here on Earth. This means that when you cry in space, your tears have nowhere to go-they just stick(粘) to your eyes.
In May 2011, astronaut Andrew Feustel experienced this during one of his spacewalks. "Tears," he said, "don't fall off of your eyes...They just kind of stay there."
Besides making your vision(视线)unclear, this can also cause physical pain. Back on Earth, tears are supposed to bring comfort to the eyes. But that's not the case in space. The space environment dries out astronauts' eyes, and when tears suddenly wet the eyes, it can cause pain rather than comfort. "My right eye is stinging(刺痛) like crazy," Feustel told his teammate during the walk.
Since gravity doesn't work in space, astronauts need some extra help to get rid of（除去） the tears. Feustel chose to rub his eyes against his helmet to wipe(擦) the tears away. Another choice is to just wait-"When the tears get big enough they simply break free of the eyes and float around," astronaut Ron Parise told The Atlantic.
There are lots of small things-things like crying-that we are so used to on Earth. We usually take them for granted until they become a problem in a totally different environment, like space.  There, astronauts can't talk to each other directly. They also can't eat or drink in normal ways. They can't even burp (打嗝), because there is no gravity to hold the food down in their stomach. If they do burp, they just end up throwing up（呕吐）everything in their stomach, according to the UK National Space Center.
Therefore, perhaps it's only space explorers who can honestly say: "Gravity, you're the best."
【小题1】From Paragraphs 2 and 3 , we can know that_______.

根据下列句子及所给单词的首字母写出所缺单词。在填写答卷时，要求写出完整单词。 (每空限填一词)
【小题1】He is very smart．He went to university at the a   of 15．
【小题2】Never cross the street when the traffic lights are r   ．Wait until it’s green．
【小题3】It doesn’t look like rain，so you needn’t b     your umbrella with you．
【小题4】I miss my family and really feel l     without any friends in this new city．
【小题5】Where is my watch?I can’t f     it．

Once there was a father and a son. They were ill-tempered(坏脾气的) and never gave way to others.
One day the father decided to _46___some friends to dinner in his house. He __47____ his son to buy some meat in town. When the son got _48____his father wanted, he turned back and walked towards the town gate. Just then a man was coming from the outside. The gate wasn’t __49___enough to let two men in and out at the same time. But __ 50 of them would give way to the other. They___51___ straight face to face inside the gate hour after hour. But the father was worried. " What shall I do? My son hasn’t____52___ yet. I can’t wait any longer.” He wanted to know what the ___53____ with his son was. So he left his friends at home, and he himself went to the town to look for his son.
“You may first take the ___54_____ home for my friends. Let me stand here against him ____55____.” He said to his son when he knew what had happened.

The word“day”has two meanings. When we talk about the number of days in a year, we are using“day”to mean 24 hours. But when we talk about day and night, we are using“day”to mean the time between sunrise and sunset. Since the earth looks like a ball, the sun can shine on only half of it at a time. Always one half of the earth is having day and the other half night. A place is moved from day into night and from night into day over and over by the spinning（旋转）of the earth. At the equator（赤道）day and night are sometimes the same length（长度）. They are each twelve hours long. The sun rises at 6 o’clock in the morning and sets at 6 o’clock in the evening. For six months the North Pole is tilted（倾斜）toward the sun. In those months the Northern Hemisphere（半球）gets more hours of sunlight than the Southern Hemisphere. Days are longer than nights. South of the equator nights are longer than days. For the other six months the North Pole is tilted away from the sun. Then the Southern Hemisphere gets more sunlight. Days are longer than nights. North of the equator nights are longer than days. Winter is the season of long nights. Summer is the season of long days.
【小题1】A place is moved from day into night and from night into day over and over by ____ of the earth.

What is your favorite color? Do you like yellow, orange, or red? If you do, you must be an active person who enjoys life. Do you like blue? Then you are probably quiet, shy, and would rather follow than lead.
Colors do influence our moods (情绪). A yellow room makes most people feel more cheerful and more relaxed than a dark green one; and a red dress brings warmth and cheer to the saddest winter day. On the other hand, black is depressing(令人压抑的). There was a black bridge over the Thames River, near London. The number of people who killed themselves on that bridge used to be larger than on any other bridge in the area -- until it was repainted green.[来
Light and bright colors make people not only happier but also more active. In the factory, the workers will work better, harder, and have fewer accidents when their machines are painted orange rather than black.
【小题1】 An active person may like