- 首页
- 外语考试
- 托业考试（TOEIC）
- 专题热点
- 正文
托业考试(TOEIC)阅读知识整理32
托业考试（TOEIC）网为大家精心整理了大量托业考试(TOEIC)阅读知识整理的资料和大家共同分享，欢迎大家前来我站学习，下面是小编为大家整理的托业考试(TOEIC)阅读知识整理的内容，希望会对大家有所帮助！
Lava
Lava is magma that breaks the surface and erupts from a volcano. If the magma is very fluid, it flows rapidly down the volcano’s slopes. Lava that is more sticky and less fluid moves slower. Lava flows that have a continuous, smooth, ropy, or billowy surface are called pahoehoe (pronounced pah HOH ee hoh ee) flows; while a a (pronounced ah ah) flows have a jagged surface composed of loose, irregularly shaped lava chunks. Once cooled, pahoehoe forms smooth rocks, while a a forms jagged rocks. The words pahoehoe and a a are Hawaiian terms that describe the texture of the lava. Lava may also be described in terms of its composition and the type of rock it forms. Basalt, andesite, dacite, and rhyolite are all different kinds of rock that form from lava. Each type of rock, and the lava from which it forms, contains a different amount of the compound silicon dioxide. Basaltic lava has the least amount of silicon dioxide, andesitic and dacitic lava have medium levels of silicon dioxide, while rhyolitic lava has the most.
编辑推荐：