A
In the future we might live somewhere other than Earth, like Mars. Some people ask how this will be possible. Well, Mars is in fact a lot the same as the earth. The days are almost the same as those on the earth. However, the two planets vary in temperature.
Since there is mostly carbon dioxide on Mars, it would be quite difficult for a human to just land on it. So, special types of homes and space suits have to be designed. The space suits should be almost like the ones astronauts use now, and except that they have to be warmer so that the astronauts can survive the cold temperatures. The space suits must also be able to withstand(承受) high pressure and potentially dangerous radiation that can kill.
The houses should be similar to our homes today with a slight difference. All of the houses and other buildings should be built inside a large dome(圆顶状物) or bubble. The domes should be made out of glass, and would also be able to prevent radiation from affecting the people inside. The domes will be connected to a machine (like plants which turn carbon dioxide into oxygen).
With Mars’ population growing, how would the people on its surface get fresh food and water? Just like humans use domes, they can also use domes to grow plants. However, the domes where the plants are grown must be built to expand. Once we upgrade the domes to a larger size then we can grow more food by cultivating(种植) more plants. To get the food or come in connect with other domes, there will be long narrow tunnels like roads that connect to each dome separating them by several doors so that the pressure in each dome can remain the same.
On Mars, so many other things are available to us. As humans, we can have access to rare and fairly expensive metals that aren’t very easy to get hold of on Earth, and a colony on Mars enhances(提高) our chances of finding these metals. So when someone here on Earth says that going to Mars is impossible, please tell them that they’ll never know it until they try and they may try very soon. After all it’s our future. Why not make it on Mars?
21. It is difficult for humans to live on Mars because of all the following EXCEPT _________.
A. too much radiation B. cold temperature
C. lack of enough oxygen D. lack of houses
22. One of the reasons why we are eager to explore Mars may be that _________.
A. we can find rare and expensive metals there easily
B. we’ll get too bored to live on the earth in the future
C. our technology will become much advanced
D. we want to know more about the unknown world
23. What is the author’s attitude towards living on Mars? _________.
A. Pessimistic B. Uncertain C. Optimistic D. Opposed
