托?？荚囍虚喿x一塊最是考察大家的英語綜合能力。想要提高英語閱讀能力，除了詞匯量的積累，也需要在積累閱讀背景知識，同時多做題目提高閱讀速度。下面是出國留學(xué)網(wǎng)(www.liuxue86.com)托福頻道小編為大家整理的關(guān)于LAVA的閱讀材料，希望對大家有所幫助!
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.
>>>點(diǎn)擊進(jìn)入托福頻道了解更多相關(guān)信息