2017年10月14日托福阅读真题+题目+答案：Understanding Insects through Fossils

2017年10月14日托福阅读真题+题目+答案：Understanding Insects through Fossils

Although it has been estimated that insects account for roughly one-third of all animal species alive today, insects are, on the whole. poorly represented in the available fossil record, where many species are known from just a single specimen, and a high proportion of fossil insects come from exceptional fossil deposits that are sporadically distributed in time and space. Nonetheless, about 40.000 species of insects have been described as fossils, with many more awaiting description. Foremost among insect-rich deposits are ambers in which complete external preservation of insects is routine. Amber is the fossilized resin of a few particular kinds of trees. Oozing out of the bark, this resin had the ability to trap and surround insects, as well as other small animals, protecting them from the normal processes of organic decay as it hardened into transparent, yellow or orange amber. The chemical process of "amberization" could take up to 10million years. During this time, it was common for amber initially buried in the soil to be washed out by rivers and redeposited in the sea.

1.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage?Incorrect choices change the meaning in important ways or leave out essential information.

A Insects, which account for roughly one-third of all animal species alive today, are also represented in the fossil record.

B The available fossil record offers a limited picture of early insects because it provides relatively few specimens.

C Many insect species are represented in the available fossil record by just a single specimen.

D Many fossil insects have been found in the exceptional fossil deposits that are associated with a variety of times and places.

2.Paragraph 1 supports all of the following statements about amber EXCEPT:

A It is formed from a substance produced by certain types of trees.

B It is sometimes transported away from the place where it was produced

C It is fossilized through a quick chemical process.

D It can preserve the outer body parts of organisms covered in it.

Although the oldest amber comes from the Carboniferous period(360-290 million years ago)， the great majority of amber deposits were formed between the start of the Cretaceous period(146 million years ago)and the present. They provide priceless windows on the insects and other small animals living at the time in the forests where amber-producing trees grew. Elsewhere in the fossil record, insects can be found in fine-grained sedimentary rocks, such as clays and silts deposited in freshwater lakes and sluggish rivers. Unlike the insects in amber, these fossils generally comprise only fragments. particularly of wings or wing cases, although more complete examples can be found, such as the dragonflies of the famous Jurassic Solnhofen Limestone of Bavaria.

3.The word "priceless" in the passage is closest in meaning to

A highly valuable

B very clear

C long-lasting

D easy-to-use

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