文档介绍：2021英语四级考试阅读讲义(十七)_英语四级考试阅读
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Unit 5
Part Ⅱ Reading Comprehension
(35 minutes)
Directions: There are 4 reading passages in this part. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice and mark the corresponding letter on the Answer Sheet with a single line through the centre.
Passage One
Questions 21 to 25 are based on the following passage:
There are desert plants which survive the dry season in the form of inactive seeds. There are also desert insects which survive as inactive larvae (幼虫). In addition, difficult as it is to believe, there are desert fish which can survive through years of drought (干旱) in the form of inactive eggs. These are the shrimps (小虾) that live in the Mojave Desert, an intensely dry region in the south-west of the United States where shade temperatures of over 50℃ are often recorded. The eggs of the Mojave shrimps are the size and have the appearance of grains of sand. When sufficient spring rain falls to form a lake, once every two to five years, these eggs hatch (孵化). Then the water is soon filled with millions of tiny shrimps about a millimetre long which feed on tiny plant and animal organisms which als