题目内容：

    On Dec 22, China became the third country in the world after Japan and the US to have a carbon dioxide（CO2）monitoring satellite.

Named Tansat, as "tan" is the Chinese word for carbon, the satellite moves around Earth at about 700 kilometers above the ground. There, it can “see” clearly how much CO2 there is in the air and how it is moving.

How is TanSat able to do that？When sunlight travels through the air, the CO2 molecules（分子）take in different colors from the light. The satellite then looks at these colors to find out how much CO2 there is in the air.

“The TanSat has very good vision（视力）, and it can tell changes in CO2 as small as 1 percent, ” said Yin Zeng shan, one of the satellite's designers at the Chinese Academy of Sciences, according to Xinhua News Agency.

But there is a question. When CO2 can already be measured from ground stations, why do we need a satellite that does the same thing？

The truth is that they don't do exactly the same thing. According to Zhang Peng, vice director of the National Satellite Meteorological Center, the data from ground stations is limited and it does not cover the ocean area, which takes up more than 70 petcent of Earth's surface.

But TanSat has solved the problem. It has a bird's eye view of the Earth, covering both the land and the ocean. It can also change its mode（模式）and position when looking at the ocean area because the water can reflect light. This light may change the data if its normal mode is used.

More importantly, China is now working on its goal of producing less CO, , starting from 2030 or earlier. To meet that goal, it will need to keep track of every bit of progress that it's making.

And with TauSat, China will have first-hand, detailed data of CO2 emissions in different areas, provinces and parts of the ocean, no longer having to use data from Japan and the US.

1.Which of the following about TanSat is TRUE？

A.It collects the CO2 in different areas above the ground.

B.It gets CO2 data by studying the colors of air.

C.It has been developed with the help of Japan and the US.

D.It has different modes to suit different weather conditions.

2.By reporting that the TanSat has very good "vision", the article shows that_______________.

A.the satellite uses many different kinds of cameras.

B.the satellite is very sensitive.

C.the satellite can capture every change in CO2.

D.the satellite can reflect light at 700 kilometers above the ground.

3.What can be concluded from the last paragraph?

A.TanSat is specially designed to reduce China's CO2 emissions.

B.China did not have any detailed data of CO2 emissions before.

C.TanSat will play a key role in helping to reduce China's CO2 emissions.

D.China is going to share its data of CO2 emissions with other countries.

4.What could be the best title for the passage?

A.Making great achievements B.Cutting CO2 emissions

C.Monitoring the ocean D.Checking more carbon