大家，帮忙分析分析这两道题～～不怕一万就怕万一啊！

pt0627UID: 2494934

50.From a draft textbook manuscript submitted to a publisher.

"As Earth was being formed out of the collision of space rocks, the heat
from those collisions and from the increasing gravitational energy of the
planet made the entire planet molten, even the surface. Any water present
would have evaporated and gone off into space. As the planet approached
its current size, however, its gravitation became strong enough to hold
gases and water vapor around it as an atmosphere. Because comets are
largely ice made up of frozen water and gases, a comet striking Earth then
would have vaporized. The resulting water vapor would have been retained
in the atmosphere, eventually falling as rain on the cooled and solidified
surface of Earth. Therefore, the water in Earth's oceans must have
originated from comets."

当地球在太空岩石的撞击作用下形成的时候，撞击产生的热量和行星越来越大的重力能量使整个行星融化，甚至包括表面。当时存在的任何水分都会蒸发并消失在太空。然而，当行星接近现在的大小的时候，它的重力强到了足以保持其周围的气体和水蒸气来形成大气层。由于彗星主要是由冻结的水和气体组成的冰，撞击地球的彗星将会蒸发。产生的水蒸气将被留在大气层，最终以降雨的形式落在地球已冷却而且坚硬的表面。因此，地球海洋的水分一定是来自彗星。

109.The following appeared in a letter to the editor of the Maple City
newspaper.

"Twenty years ago Pine City established strict laws designed to limit the
number of new buildings that could be constructed in the city. Since that
time the average housing prices in Pine City have increased considerably.
Chestnut City, which is about the same size as Pine City, has over the
past twenty years experienced an increase in average housing prices
similar to Pine City, but Chestnut City never established any laws that
limit new building construction. So it is clear that laws limiting new
construction have no effect on average housing prices. So if Maple City
were to establish strict laws that limit new building construction, these
laws will have no effect on average housing prices."

20年前Pine City建立了严格的法令来限制该市未来建造的高层建筑的数量。从那以后Pine City的平均房价显著上涨。和Pine
City差不多同等规模的Chestnut City在过去20年中经历了和Pine City类似的房价上涨，但Chestnut
City从未建立任何限制高层建筑的法令。因此限制高层的法令对于平均房价没有影响。所以如果Maple
City建立限制新的高层建筑的法令的话，这种法令不会影响平均房价。

咖啡盐UID: 2973669

最讨厌A50这种纯科普滴题目，麻烦....