main idea
Paragrah 2: main idea
An alternative explanation is that asteroid planets and proto-planets that clumped together
to form Earth that carried enough water in their rock minerals to explain our oceans.
Paragraph 2: sentence analysis
1. probe
2. discrete clumps
3. traction
4. thaws
Explain question 4
paragraph 2: Intriguingly, in October 2015 it was reported that-as this comet slowly thaws-molecular oxygen (02) escapes in a constant and high proportion (1% to 10%) relative to water which suggests that the comet also contains a surprising amount of primordial (ancient) oxygen, which was incorporated during the comet's formation.
paragraph5: application of vocabulary
1. weathered
2. basin
Paragraph 4 : main idea
Paragraph 2 : sentence analysis
有趣的是，2015年10月有报道称，随着这颗彗星慢慢解冻，分子氧（02）相对于水以恒定且较高的比例（1%至10%）逸出，这表明彗星还含有惊人的原始（古代）氧，这是在彗星形成过程中融入的。
Paragraph 3: explain question 6
Thus, a theory was developed that the asteroids planetesimals and protoplanets that clumped together to form Earth had carried enough water in their rock minerals to explain our oceans.是答案的定位句
Paragragh 1: Application of vocabulary
1. speculation
2. was stripped away
3. collision
4. retain
5. composition, meteorite
6.notably
Paragraph 1: main idea of paragraph 1
Scientists have discovered that the collisions with icy comets or similiar gas- and water-rich materials brought water to Earth after the planet had sufficiently cooled to retain it.
Paragraph 1: sentence analysis
通过比较陨石气体成分与地球表面以下岩石气体成分，特别是使用氪气和氙气，这两种非金属气体不会与其他物质发生反应，这一概念得到支持。
paragraph 3: explain question 5
Other work favors an alternative explanation. This work found that the hydrogen isotope ratio (the proportion of different forms of hydrogen) of ice in comets may be different from that of water on Earth. (在这里注意第二段与第三段之前的关系，第二段用一个科学工作发现解释了地球上水的来源，第二段用另一个不同的科学工作解释了地球上水的来源）
Paragraph 4 application of vocabulary
1. accumulation, dissolved mineral
2. pitted
3. corrosive
Paragraph 4： sentence analysis
工作中的关键过程是岩石和水之间的化学反应，其中溶解在水中的气体（如二氧化碳或二氧化硫）起着重要作用，因为这些气体使水更具腐蚀性。
Explain question 10
A. paragraph 1: As a consequence, it was proposed that collisions with icy comets or similar gas-and water-rich materials brought water to Earth after the planet had sufficiently cooled to retain it.
B. paragraph 3: Thus, a theory was developed that the asteroids planetesimals and protoplanets that clumped together to form Earth had carried enough water in their rock minerals to explain our oceans. It would have escaped from the planet's interior as steam, which in turn would have condensed into water at the surface and in the early atmosphere.
C. paragraph 4:It represents an accumulation of dissolved minerals over tens of millions to hundreds of millions of years. These minerals were broken up and dissolved during chemical weathering.
The chemical weathering reactions break up rock minerals into charged atoms or molecules, called ions, which are removed in solution by river water and groundwater
D. paragraph 2:Intriguingly, in October 2015 it was reported that-as this comet slowly thaws-molecular oxygen (02) escapes in a constant and high proportion (1% to 10%) relative to water which suggests that the comet also contains a surprising amount of primordial (ancient) oxygen, which was incorporated during the comet's formation. ---原始氧气在彗星中发现
E 无中生有
F 无中生有
paragraph 5: sentence analysis
考虑到盐的输入和移除速度极慢，很明显，海洋中大量的盐已经积累，因为海洋长期以来一直是盐运输的终点站。