2019年托福考试阅读试题：浮游生物

阅读试题中国考生来说并不是特别的难，但是要想获得高分也不是件容易的事，需要我们在备考的时候多做写模拟题，今天小编就给大家准备了这篇模拟题，在坦途网托福考试频道还有很多新的内容，现在我们先来看看这篇文章吧！

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

这就是这篇文章的全部内容了，我们在阅读的时候，可以不仅仅是做题，我们还可以在文章中摘抄一些比较优秀的句子作为写作素材，一举两得，小编会持续为大家更新很多相关的内容，做好每月托福考试时间的变更，希望能够帮助正在努力复习的小伙伴们！