托福阅读真题练习：浮游生物的文本+真题+答案

2017年12月11日17:37 来源：小站整理

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托福阅读如何进行备考?除了大量的托福词汇储备以外，大家可能最需要的就是托福阅读真题的练习。那么除了官方真题Official你还有哪些托福阅读真题进行练习呢?今天小编就为大家整理了托福阅读真题100篇：浮游生物的文本、题目以及答案，希望可以帮助到大家。

托福阅读文本：

Perhaps one of the most dramatic and important changes that took place in the Mesozoic era

occurred late in that era, among the small organisms that populate the uppermost, sunlit portion of

the oceans — the plankton. The term "plankton" is a broad one, designating all of the small plants

and animals that float about or weakly propel themselves through the sea. In the late stages of the

Mesozoic era, during the Cretaceous period, there was a great expansion of plankton that

precipitated skeletons or shells composed of two types of mineral: silica and calcium carbonate.

This development radically changed the types of sediments that accumulated on the seafloor,

because, while the organic parts of the plankton decayed after the organisms died, their

mineralized skeletons often survived and sank to the bottom. For the first time in the Earth's long

history, very large quantities of silica skeletons, which would eventually harden into rock, began

to pile up in parts of the deep sea. Thick deposits of calcareous ooze made up of the tiny remains

of the calcium carbonate-secreting plankton also accumulated as never before. The famous white

chalk cliffs of Dover, in the southeast of England, are just one example of the huge quantities of

such material that amassed during the Cretaceous period; there are many more. Just why the

calcareous plankton were so prolific during the latter part of the Cretaceous period is not fully

understood. Such massive amounts of chalky sediments have never since been deposited over a

comparable period of time.

The high biological productivity of the Cretaceous oceans also led to ideal conditions for oil

accumulation. Oil is formed when organic material trapped in sediments is slowly buried and

subjected to increased temperatures and pressures, transforming it into petroleum. Sediments rich

in organic material accumulated along the margins of the Tethys Seaway, the tropical east-west

ocean that formed when Earth's single landmass (known as Pangaea) split apart during the

Mesozoic era. Many of today's important oil fields are found in those sediments — in Russia, the

Middle East, the Gulf of Mexico, and in the states of Texas and Louisiana in the United States.

托福阅读题目：

1. What does the passage mainly discuss?

(A) How sediments were built up in oceans during the Cretaceous period

(B) How petroleum was formed in the Mesozoic era

(C) The impact of changes in oceanic animal and plant life in the Mesozoic era

(D) The differences between plankton found in the present era and Cretaceous plankton

2. The passage indicates that the Cretaceous period occurred

(A) in the early part of the Mesozoic era

(B) in the middle part of the Mesozoic era

(C) in the later part of the Mesozoic era

(D) after the Mesozoic era

3. The passage mentions all of the following aspects of plankton EXCEPT

(A) the length of their lives

(B) the level of the ocean at which they are found

(C) their movement

(D) their size

4. The word "accumulated" in line 8 is closest in meaning to

(A) depended

(B) matured

(C) dissolved

(D) collected

5. According to the passage , the most dramatic change to the oceans caused by plankton during

the Cretaceous period concerned

(A) the depth of the water

(B) the makeup of the sediment on the ocean floor

(C) the decrease in petroleum-producing sediment

(D) a decline in the quantity of calcareous ooze on the seafloor

6. The "white chalk cliffs of Dover" are mentioned in line 14 of the passage to

(A) show where the plankton sediment first began to build up

(B) provide an example of a plankton buildup that scientists cannot explain

(C) provide an example of the buildup of plankton sediment

(D) indicate the largest single plankton buildup on Earth

7. The word "prolific" in line 17 is closest in meaning to

(A) fruitful

(B) distinct

(C) determined

(D) energetic

8. The word "ideal" in line 20 is closest in meaning to

(A) common

(B) clear

(C) perfect

(D) immediate

9. The word "it" in line 22 refers to

(A) biological productivity

(B) oil

(C) organic material

(D) petroleum

托福阅读答案：

CCADB CACC

以上就是小编为大家整理的托福阅读100篇真题练习：浮游生物的文本、题目以及答案，大家在托福阅读考试进行备考的过程当中也可以拿这些题目来进行练习，相信对于你的托福阅读考试成绩提升会很有帮助。最后，小编预祝大家托福考试能取得理想的成绩。