目前，地球上能供养人类的资源有限，一些资源甚至正在耗尽。例如，地球上的氧气越来越少了。因此，一些人认为人类应该花更多的时间和金钱来探索太空和宇宙的秘密。太空探索直接产生了许多卫星和其他高端产品。根据卫星返回地球的数据和天气模式，科学家可以通过分析做出准确的天气预报。探索太空是浪费时间和金钱的论点是很肤浅的。最后，应该继续进行太空探索。

Currently, there are     1     resources on the globe to     2     mankind, and some resources are even     3    . For example, there is less and less     4     on Earth.     5    , some people     6     that humans should spend more time and money exploring space and     7     of the universe. Space exploration has directly     8     many satellites and other     9     products. According to the data and weather     10     sent back to Earth by satellites, scientists can make an accurate weather forecast through     11    . The     12     that exploring space is a waste of time and money is very     13    .     14    , space exploration should be continued.

No matter how exciting space exploration sounds, there’s an important point that needs to be considered: food supplies. Right now, astronauts typically       1     (依赖) dry food in airtight bags and cans, since there are strict weight limits on items taken into space. Foods that we     2     (认为是理所当然的), such as fresh fruit and vegetables, are out of the question for space explorers.

For those who     3     (有强烈的愿望) to grow food during space flights, they’ve faced many difficulties, including the absence of gravity, and a lack of soil, air and humidity (湿度). However, growing food to add and minimize the food that must be carried to space will be increasingly important on long-duration flights into space. Recently, a leading team has worked out how plants can absorb nutrients from human urine (尿). Human urine is 95 percent water, with the other 5 percent    4     (构成；组成) nutrients which are harmful to the human body but not to plants, and it could supply three to four out of the six nutrients that plants need. By recycling liquid waste and producing food, an efficient cycle will be created.

And most importantly, the duration of space flights will be greatly extended to “20 years of flight”, meaning we may be soon sending astronauts on flights to Mars, or even beyond.

Are we a    1    ? What’s out there ?” Looking up at the s    2     , people have always wanted to l    3    more about space , and scientists work h     4    to find answers . They m    5     vehicles to carry b     6     people into space to find out the s    7     of the universe.They also really wish to d    8     other planets that are s    9    enough to s    10     life .