天文学在托福听力里大家都会觉得特别难，为什么会觉得难，原因大致可以分为三点。
原因1 ：生词多
原因2 ：提到的理论或假说非常复杂
原因3 ：文章结构不清楚
解决方法：
1.背单词不要围绕著专有名词背，多背天文学文章中的动词 e.g. orbit / revolve
2.假说内容复杂，就主要听结果 或 可信度 e.g. contradiction 有反驳的意思，不可信
3.文章结构现在我们可以了解一下 TPO 30 L3 Astronomy class - Jarosite
通过以上描述，有的考生还是认为不容易理解，下面Kobe老师为大家列举了具体的实例，希望帮助各位考生在这方面理解的更加透彻。
开头：
火星上存在生命的证据：Jarosite
文章主体(火星上存在生命的证据)：
1.What is it?
Jarosite黄钾铁矾为何物
2.How it forms?
在地球上形成的条件：
a Acidic water 高酸性水→生命
b 微生物参与
3.How to analyse a certain minerals ?
3、MOA-检测火星黄钾铁矾是否有微生物的设备(寻找氨基酸)
氨基酸：地球上的20多种都是左旋的(手性)
4.Analyzer advantages
MOA的优势：
a、能够收集土壤样本，并且在火星上立刻进行分析,消除污染的风险
b、不仅能检测出氨基酸的存在还可以检测出氨基酸的旋的方式
5.Conclusion / Future Development ?
结论：
如果找到氨基酸及旋的方向，像在地球上的氨基酸一样向左，或是向右都是很有趣的。
左旋→与地球一样
右旋→火星生命与地球完全不一样
題目：
1.What is the lecture mainly about?
A. Evidence proving that water was once on Mars
B. Scientific analyses currently being done on mineral samples from Mars
C. Recent developments that could help determine whether life ever existed on Mars
D. An approach to determining whether amino acids on Earth originated on Mars
正确答案，C。内容主旨题。开头介绍有很多关于火星有生命的讨论，主要因为一些重要的发现和发明。下文以黄钾铁矾为例具体讨论。所以主要内容为C。
7.What was discovered on Mars that suggests water once existed there?
A. Microorganisms that can form only in the presence of water.
B. A mineral that can form only in the presence of water.
C. Proteins that have the same structure as proteins found on Earth.
D. Large deposits of iron and potassium that can form only in the presence of water.
正确答案，B。细节题。文中听到：一个主要的发现是水出现在火星上因为发现黄钾铁矾。这种矿物在地球上形成时需要高酸度的水。因此推测出火星上有水。
8.How might jarosite found on Mars differ from jarosite found on Earth?
A. Mars jarosite and Earth jarosite might have been created by different processes.
B. Mars jarosite might have been formed without water.
C. Mars jarosite might not contain as much iron or potassium as Earth jarosite.
D. Mars jarosite might be more acidic than Earth jarosite.
正确答案，A。细节题。文中提到：地球上黄钾铁矾的形成需要微生物，理论上讲，没有生命体的帮助也可以形成黄钾铁矾，所以地球和火星黄钾铁矾的不同之处可能是两者产生的过程不同。
9.According to the professor,what are two important capabilities of the microfabricated organic analyzer?Click on 2 answers
A. It can accurately test for the presence of water.
B. It can analyze soil samples without returning them to Earth.
C. It can return soil samples back to Earth quickly.
D. It can determine the handedness of amino acids.
正确答案，B D。细节题。教授说，有机分析仪能在火星上分析样本，不用带回地球，并且有机分析仪可以测试出氨基酸旋的方向。
10.What point does the professor make about the twenty amino acids that occur on proteins on Earth?
A. They can be either right-handed or left-handed.
B. They were synthesized through abiotic processes.
C. They all have a crystalline structure.
D. They are all left-handed.
正确答案，D。态度题。教授提到地球上的氨基酸的旋都是左旋。因此选D
11.What would a prevalence of right-handed amino acids in mineral samples collected on Mars indicate?
A. That amino acids on Mars probably originated on Earth
B. That amino acids existed on Mars long before they existed on Earth
C. That a type of microorganism may have existed on Mars that is different from any on Earth
D. That left-handed amino acids are probably present in some minerals on Mars
正确答案，C。推断推理题。因为地球上的生物都是左旋，所以地球上的大部分氨基酸是左旋，那么如果火星上的氨基酸是右旋，火星上的生命也是右旋，这样火星上的生命可能与地球的完全不同。