托福机经阅读：
1. 关键词：water deposit; delta, downstream/upstream sediments
最后一段有插入提是关于说The Mississippi River Delta;人们保持channel of The Mississippi River 是为了不让河水改变到别的地方
2. Silent film and synchronous sound
第一题，爱迪生为什么发明了Kentucky
为了synchronous sound改进的system 有什么缺陷
3. atmosphere of Venus，现在地球上水多，大气层相对稀薄，金星上大气层后的多。提出的假设，很久以前金星和地球有同样的大气构造，金星上也有水The atmosphere of Venus is very hot and thick提出假设：在形成初期可能和地球的成分相似，都含有大量水，但是离太阳距离过近，水蒸发了，连二氧化碳都能因为高压从石灰石里跑出来，温室效应就更强了。
相似： Both Earth and Venus have small amounts of water atmosphere. However, Venus' atmospheric water is about all the water on the planet. Terrestrial planets get much of their atmospheres from gases released from their interiors, primarily through volcanic formation. Volcanoes on Earth release large amounts of both water vapor and carbon dioxide, and it is likely that this is also the case for volcanoes on Venus.
Most of the carbon dioxide on Earth is now dissolved in the oceans and in rocks such as limestone, which is found in the oceans. Venus, however, would have had a higher surface temperature due to its position nearer the Sun: as a result, any liquid water on the plant's surface quickly evaporated, and the carbon dioxide remained in the atmosphere.
