希望高人点评--A50地球海洋的形成

h923682801UID: 2822058

小弟对Argument是越复习越觉得糟。总没什么进步。连四百字都达不到。希望高人点评。
In this argument , the arguer concludes that the water in Earth's oceans must have originated from comets.  This argument  might seem reasonable at first glance. However, several logical flaws make it unconvincing as all.

First of all, the arguer assumes that comets striking Earth would all vaporate and the resulting water would be retained in the atmosphere.  No evidence has been provided to show that the collision between Earth and comets with will surely result in the evaporation of comets although they are made up of ice.  Furthermore, the arguer doesn't inform us how much of the water evaporated from comets will be retained in the atomosphere.  It is highly possible that only a small portion of the water will be captured by Earth.  Without clearer evidence ,the arguer cannot make me convinced of the process of how Earth gets water from comets.

Secondly, the arguer assumes that water captured from comets is suffient to form oceans on Earth.  How much water can Earth get from one collision with comets?  How many times of collisions is needed to form oceans which contain  such a large amount of water?  Without these statistics ,I cannot come to the assumption that the water in oceans is from comets.

Finally, the arguer does not take other possible scenarios which may result in oceans on Earth into consideration.  It is possible that the water in oceans also comes from Earth itself .  It is possible that rocks can react to form water after the hot Earth cooled down.  Thus, the water in oceans might be partly from comets from comets while the majority is from Earht itself.

In conclusion, the argument is poorly reasoned for lack of clearer evidence.  To bolster it ,the arguer should provide clear evidence that 1)comets collide with Earth will evaporate and be retained by Earth; 2)water from comets is suffient to form oceans of Earth; 3)no other process has contributed to the formation of ocean water.

h923682801UID: 2822058

请求各位斑竹帮忙啊！