Question

Dodder is an unusual and unwanted plant that attacks other plants. Except for its flowers, the plant looks like spaghetti, a kind of noodles in the shape of long thin pieces that look like string when they are cooked. Its almost leafless, thread-like stems (茎) hang down on top of other plants that dodder needs to stay alive. Dodder does not produce its own food. Instead, it steals food from other plants. It feeds by sucking juices from the plant which is wrapped around, often making its host very weak or even killing it.

Dodder can find other plants by their smell. When a young dodder plant starts growing, it follows the smell of plants it prefers, like tomato plants, potato plants, or other farm crops. Unlike most plants that usually grow in the direction of light or warmth, a dodder plant will grow in the direction of, for example, tomato smell—if a tomato happens to be growing nearby.

However, a young dodder plant must find a host plant quickly. It no longer needs its root once it is attached to the host and wrapped around it. If it cannot catch a smell of a potential host within a few days, it will dry up and disappear—even if there is plenty of water around. Once it finds a host, the young dodder plant will attach itself to it and start growing faster. At that point the dodder plant will drop its root.

Dodder is thus a difficult weed to manage and a real headache for farmers. When it does get out of hand, dodder can greatly reduce a farmer’s harvest or even destroy crops completely. Before sowing their produce, especially farmers in warm parts of the world often check to make sure no unwanted dodder seeds have mixed with their crop seeds. This is a good way to stop dodder plants from making their way to a crop field secretly.

1.Why does the author mention spaghetti in the first paragraph?

A. To analyze the content of some food.

B. To describe the shape of dodder plants.

C. To explain where the dodder plants come from.

D. To argue that dodder plants can be used.

2.What will happen if a dodder plant starts growing where there are no other plants around?

A. It will die sooner or later.

B. It will grow deep roots.

C. It will attract other plants.

D. It will cover the entire area of soil.

3.What can be inferred from the passage?

A. Dodder does not produce its own food.

B. Dodder can affect farmers’ income.

C. Dodder can only survive in the shade.

D. Dodder only grows in the warm areas.

4.What is the main topic of the passage?

A. A new variety of farm crops.

B. Plants that are harmful to humans.

C. The special abilities of a dangerous plant.

D. Recent improvements in farming methods.

Answer

1.B

2.A

3.B

4.C

【解析】文章介绍了一种有特殊生长习性，危害农作物生长的攀附植物菟丝子。

1.B

推理判断题。根据第一段the plant looks like spaghetti, a kind of noodles in the shape of long thin pieces that look like string when they are cooked.作者把dodder和意大利面条相比是用人们熟悉的事物来说明dodder的形状，故选B.

2.A

细节推理题。根据第三段If it cannot catch a smell of a potential host within a few days, it will dry up and disappear-even if there is plenty of water around.可知dodder如果找不到可以攀附的植物，它就会变干死亡。故选A.

3.B

推理判断题。根据最后一段When it does get out of hand, dodder can greatly reduce a farmer’s harvest or even destroy crops completely.可知当它失控时，菟丝子可以大大减少农民的收成，甚至完全毁坏庄稼。由此可见dodder会影响农民们的收入。C、D两项说法错误，A项正确，但文中有原句，不是推断出来的。故选B.

4.C

主旨大意题。根据首句Dodder is an unusual and unwanted plant that attacks other plants.和下文对dodder特殊生长习性和危害的叙述，可知本文主要在介绍这种特殊的又有危害的植物，C项是本文的主题，故选C.

【名师点睛】

推理判断题属于主观题，是层次较高的题目。它包括判断和推理题。这两类题常常相互依存，推理是为了做出正确的判断，正确的判断又依赖于合乎逻辑的推理。此类题要求在理解表面文字的基础上，做出判断和推论，从而得到文章的隐含的意思和深层的意思，也就是通过文章中的文字信息，上下逻辑关系及事物的发展变化等已知的信息，推断出作者没有直接表达的态度和观点。

本文推理判断题的考法：

1)推测文章的观点或结论。小题3考查从文中得出的观点，根据最后一段When it does get out of hand, dodder can greatly reduce a farmer’s harvest or even destroy crops completely.可知当它失控时，菟丝子可以大大减少农民的收成，甚至完全毁坏庄稼。由此可见dodder会影响农民们的收入。C、D两项说法错误，A项正确，但文中有原句，不是推断出来的。

2)推测作者写作目的或意图。小题1考查作者比喻的意图，根据第一段the plant looks like spaghetti, a kind of noodles in the shape of long thin pieces that look like string when they are cooked.作者把dodder和意大利面条相比是用人们熟悉的事物来说明dodder的形状。