托福阅读历年真题精选8_第2页

24. 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

(C) it is combined with alkalies

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

25. 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.

(C) Its presence indicates inferior clay.

(D) It is a major component of clay.

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

(A) iron

(B) feldspar

(C) granite

(D) clay

27. 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

(C) have a smooth texture

(D) are highly decorated

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

(A) reduce

(B) explain

(C) combine with

(D) list all of

29. 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.

(C) Only certain types of clay are appropriate for making china teacups.

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