单选题Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates. Frost rings do not appear in any of the fossilized deciduous trees that have been found in Antarctica. Hence, it is unlikely that such frosts occ

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单选题

Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates. Frost rings do not appear in any of the fossilized deciduous trees that have been found in Antarctica. Hence, it is unlikely that such frosts occurred in Antarctica at the time the fossilized trees lived.　 Which of the following is an assumption on which the argument depends?

There are fossilized nondeciduous trees from Antarctica that bear frost rings.

Deciduous trees are more likely to bear frost rings than are other tree varieties.

The process of fossilization does not completely obscure frost rings in deciduous trees.

Present-day deciduous trees are more sensitive to changes in temperature than were the deciduous trees of ancient Antarctica.

Prolonged and unseasonable frosts that might have occurred in Antarctica when the now-fossilized trees were still living did not always produce frost rings in deciduous trees.

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相似问题和答案

第1题：

Which of the following usually causes a tree to grow unhealthy?

A. Giving a tree a special shape and a definite height.

B. Removing small side branches and making a tree look less thick.

C. Allowing too many branches to grow in the middle.

D. Having a tree surrounded by many other trees.

正确答案：C

42．答案为C 根据第二段A tree may grow healthier by removing the branches that are locking up the centre可知树中间的枝杈不利于树木生长，C与文章内容相反，因此错误。

第2题：

Among the rings of a piston the ______one is subjected to the greatest load and temperature.

A.bottom

B.middle

C.top

D.any position

正确答案：C

第3题：

4．— Did you have anyone ______the trees?

—Yes，l had the trees ______．

A． to water ;water

B． to water; watered

C． water ; to be watered

D． water; watered

正确答案：D
4.D【解析】此题考查have的用法．have sb. do意为“让某人做……”；have sth. done意为“让某事被做”。故答案为D。

第4题：

If the phone rings again, I（）it.

Aignore

Bwill ignore

Cwill have ignored

Dwould have ignored

B
略

第5题：

We found shelter from the rain under the trees.

A: defense
B: standing
C: protection
D: room

答案：C

解析：

题干意为“我们躲在树下避雨。” 句中划线词为名词，意为“庇护，掩蔽处”。C项protection意为“保护”，例句：Every citi- zen may claim the protection of the law．每个公民都可以要求受到法律的保护。A项意为“防卫，防护”,B项意为“名声，地位”,D项意为“房间，空间”，故选C。

第6题：

Why do plants grow in some places and not in others? Why does some land have so much growing on it，while other land has almost no plants growing on it at all?

To grow plants need several things． One is warmth． In very cold places almost nothing grows． Plants also need water． In very dry parts of the earth only a few unusual plants can grow． That's why dry deserts everywhere are almost not covered by trees or grass．

Plants must also have a place in which to f，ut down their roots and grow． They find it diffi-culr to grow on hard land． The town is built on hard land． The plants here have only the soil found between the cracks of the stones Io grow in．

Another thing plants must have before they can grow is food．

Whar will happen if we try to make things grow on the sandy beach? A few plants，such as beach grass，will grow in sand，L ut most plants won-t． Even if the weather is warm enough．and we water the plants each day． Many of them will die because the sand on this beach has al-most no food for plants．

( )21． According to the passage，plants need _________ things to grow well．

A． two

B． three

C． four

D． five

正确答案：C
Ⅲ．21．C【解析】通读全文可知：植物的生长需要4个条件：1．适宜的温度；2．水;3．合适的土壤；4.养分。

第7题：

共用题干
Forests for Cities
You are standing in a beautiful forest in Japan. The air is clean and smells like plants and flowers.There are 175 different kinds of trees,and 60 kinds of birds live here.______(1) You are downtown in the city of Nara,Japan,in Kasugayama Forest,the oldest urban forest in the world.It was started more than a thousand years ago,and today it's very popular with tourists and artists.
Cities around the world are working to protect their urban forests. Some urban forests are parks,and some are just streets with a lot of trees.But all urban forests have many good effects on the environment.______(2)They also stop the noise from heavy traffic.They even make the weather better because they make the air 3-5 degrees cooler,and they stop strong winds. Urban forests also have many good effects on people. They make the city more beautiful. In a crowded area,they give people a place to relax and spend time in nature.______(3)
In some countries,people are starting new urban forests. In England,there are now 1.3 million trees in an urban forest called Thames Chase,east of London. It was started in 1990, and it has grown very fast.Walking and bicycle clubs use the forest,and there are programs for children and artists.______(4)
Some older cities don't have space for a big urban forest,but planting trees on the streets makes the city better. Scientists found that commuters（通勤人员）feel more relaxed when they can see trees.Trees are even good for business.______(5)In the future,urban forests will become even more important as our cities grow bigger. In the megacities（超大城市）of tomorrow,people will need more green space to live a comfortable life. Planting trees today will make our lives better in the future.

______(5)
A: People spend more time at shopping centers that have trees.
B: In hot countries,urban forests are cooi places for walking and other healthy exercises.
C: But you are not in rural area.
D: Trees take pollution out of the air.
E: In 2033,it will have 5 million trees.
F: It has many kinds of birds in the country.

答案：A

解析：

从后面一句的“downtown”，可以看出，前面应该有和城市相对应的词。C项的rural是农村的意思。把C项填入后语义明确，说明奈良的城市森林覆盖率高，虽然会给你身在乡村的错觉，但这就是人家的城市风貌。所以选C。
前一句讲到城市森林对环境很有益，后一句“also”明显表明空缺的一句和 also所在句子讲述的都是具体的对环境有益的方面。所以选D。
在表达方式上，B项承接了前一句“In a crowded area, they give people a place to relax and spend time in nature.”，这两个是并列句。所以选B。
前面几句有几个关键词：now 1. 3 million trees,has grown very fast。作为本段的最后一句，一般要根据前文展望一下未来趋势。综合各个选项，E项比较合适。
从前一句Trees are even good for business可以看到，此句要具体说树木会如何促进商业活动。A项正合其意。

第8题：

If the phone rings again, I () it.

A、ignore

B、will ignore

C、will have ignored

D、would have ignored

参考答案：B

第9题：

Most of the butterflies perish in the first frosts of autumn.

A:die
B:disappear
C:migrate
D:vanish

答案：A

解析：

第10题：

Which statement is true about items that have been assembled into a kit？（）

A、 Only rotating items can be part of a kit.
B、 Kits can be assembled from lotted items.
C、 Kits can be assembled from items in different storerooms.
D、 Items that have been assembled into kits do not appear in item balances.

正确答案:D

单选题Prolonged and unseasonable frosts produce frost rings in deciduous trees, which grow in moderate climates. Frost rings do not appear in any of the fossilized deciduous trees that have been found in Antarctica. Hence, it is unlikely that such frosts occ

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