老托福阅读100篇之泥土的形成及其用途_资料下载

老托福阅读100篇之泥土的形成及其用途

时间：2015-10-12 16:50:21 / 编辑：Lee

　　老托福阅读100篇相对TPO要简单一些，也是伴随托福备考学员的很重要的一份资料，对于基础薄弱，做TPO真题阅读需要过渡的考生来说再适合不过了，今天一诺留学小编给大家分享的是老托福阅读100篇之泥土的形成及其用途，希望考生认真练习。

　　泥土的形成及其用途

　　Under the Earth's topsoil, at various levels, sometimes under a layer of rock, there are deposits of clay. Look at cuts where highways have been built to see exposed clay beds; or look at a construction site, where pockets of clay may be exposed. Rivers also reveal clay along their banks, and erosion on a hillside may make clay easily accessible. What is clay made of? The Earth's surface is basically rock, and it is this rock that gradually decomposes into clay. Rain, streams, alternating freezing and thawing, roots of trees and plants forcing their way into cracks, earthquakes, volcanic action, and glaciers ?a all of these forces slowly break down the Earth's exposed rocky crust into smaller and smaller pieces that eventually become clay.

　　Rocks are composed of elements and compounds of elements. Feldspar, which is the most abundant mineral on the Earth's surface, is basically made up of the oxides silica and alumina combined with alkalis like potassium and some so-called impurities such as iron. Feldspar is an essential component of granite rocks, and as such it is the basis of clay. When it is wet, clay can be easily shaped to make a variety of useful objects, which can then be fired to varying degrees of hardness and covered with impermeable decorative coatings of glasslike material called glaze. Just as volcanic action, with its intense heat, fuses the elements in certain rocks into a glasslike rock called obsidian, so can we apply heat to earthen materials and change them into a hard, dense material. Different clays need different heat levels to fuse, and some, the low-fire clays, never become nonporous and watertight like highly fired stoneware. Each clay can stand only a certain amount of heat without losing its shape through sagging or melting. Variations of clay composition and the temperatures at which they are fired account for the differences in texture and appearance between a china teacup and an earthenware flowerpot.

　　1. The author's main point in paragraph 1 is that clay deposits

　　(A) conceal layers of rock

　　(B) can be found in various places

　　(D) must be removed from construction sites

　　2. It can be inferred from the passage that clay is LEAST likely to be plentiful in which of the following areas?

　　(A) in desert sand dunes

　　(B) in forests

　　(D) near rivers

　　3. The word "accessible" in line 4 is closest in meaning to

　　(A) buried

　　(B) improved

　　(D) workable

　　4. According to the passage , rock breaks down into clay under all of the following conditions EXCEPT when

　　(A) it is exposed to freezing and thawing

　　(B) roots of trees force their way into cracks

　　(D) natural forces wear away the Earth's crust

　　5. Why does the author mention feldspar in line 10?

　　(A) It is often used as a substitute for clay.

　　(B) It is damaged by the oxides in clay.

　　(D) It is a major component of clay.

　　6. The word "it" in line 13 refers to

　　(A) iron

　　(B) feldspar

　　(D) clay

　　7. Based on the information in the passage , it can be inferred that low-fire clays are MOST appropriate for making objects that

　　(A) must be strong

　　(B) can be porous

　　(D) are highly decorated

　　8. The phrase "account for" in line 22 is closest in meaning to

　　(A) reduce

　　(B) explain

　　(D) list all of

　　9. The passage supports which of the following conclusions?

　　(A) Clay deposits are only found deep in the Earth.

　　(B) If clay contains too much iron it will melt when fired.

　　(D) If sufficient heat is applied, all clay will become nonporous.

　　答案：BACCD BBBC

　　以上内容就是老托福阅读100篇之泥土的形成及其用途的介绍，希望对大家的托福考试有帮助。如需了解更多留学考试的相关信息，欢迎拨打一诺留学的免费热线400-003-6508或者010-62680991进行出国留学咨询，或者点击一诺留学官方网站http://www.yinuoedu.net/页面的“在线咨询”与一诺留学专家直接对话。