Question

Durian(榴莲) is probably the smelliest fruit in the world, letting out an unusual unpleasant smell which would make anyone bring up. However, nobody was aware of what gave this fruit its unique smell, so a team of researchers from Singapore decided to take a look at its genome (基因组) and find out,

Durian is well-known throughout Southeast Asia as the king of fruits, mostly because of its awful appearance and smell. However, the origin of this unpleasant smell was unknown, so researchers decided to map the genome of the fruit, and find the gene that controlled it. A group of genes, volatile sulfur compounds (含硫化合物), became very active in the fruit, and they were found responsible for resulting in the unpleasant smell.

The fruit confuses everyone with a sulfuric smell, like rotten onions and ingredients. The smell lasts long, mostly because the fruit contains more volatile sulfur compounds. Other species usually benefit from two gene copies at most, but durian has four, leading to the striking smell.

However, this smell might be an advantage for durian in the wild. Although we find it unpleasant, many animals might be attracted by it. If they eat the fruit, then they can easily spread its seeds everywhere, thus contributing to the distribution of the species.

The mapping of the durian genome also showed some other information on the species. First of all, the fruit has an impressive number of genes, namely 46,000. Also, with the help of these genes, they saw how it evolved, and discovered it was related to the cacao tree. All the other discoveries have been published in the journal Nature Genetics.

Despite the striking smell, many people actually enjoy eating the fruit. However, not all durian species are edible, and some of them may even cause damage to our health, Even so, the fruit is often imported, significantly contributing to the economy.

1.What give durian its unique smell?

A. Onions nearby.

B. Two gene copies.

C. Rotten ingredients in it.

D. Volatile sulfur compounds.

2.What does the underlined word “evolved” in Paragraph 5 probably mean?

A. Developed.

B. Escaped.

C. Predicted.

D. Tolerated.

3.What can we infer from the text?

A. No birds enjoy eating durian.

B. Durian can be planted all over the world.

C. Some of durian species can not be eaten.

D. Durian has no relationship with the cacao tree.

4.What’s the best title for the text?

A. What’s Durian?

B. The Influence of the Smell

C. The Distribution of Durian

D. The Mystery of the Unpleasant Smell of Durian

Answer

1.D

2.A

3.C

4.D

【解析】本文为说明文。榴莲可能是世界上最臭的水果，但没有人知道是什么让它有这么独特的气味。新加坡的研究者决定找出原因。他们绘制了水果基因图，从中找出导致难闻气味的原因就是水果中含有的挥发性硫化合物（South-Type）非常活跃，导致这种难闻的气味。这种气味对于野外生存榴莲来说有利于吸引动物来吃这种水果，并进而传播种子。

1.细节理解题。根据第二段“so researchers decided to map the genome of the fruit, and find the gene that controlled it. A group of genes, volatile sulfur compounds (含硫化合物), became very active in the fruit, and they were found responsible for resulting in the unpleasant smell.”可知，研究人员找到一组基因——挥发性硫化合物（South-Type），在水果中非常活跃，发现是它们导致了这种难闻的气味。故选D项。

2.猜测词义题。根据倒数第二段内容可知，研究者画出了榴莲的基因图。通过基因图，发现了这种水果的基因庞大，有46000条基因。在这些基因的帮助下，他们了解了榴莲的基因如何演变（evolved）的，并发现榴莲与可可树有关。分析选项（A. develop [生物学]使进化；B.Escape逃脱； C. Predict预言，预测；D. tolerated忍受，容忍。）可知，只有A项develop（使进化），与划线词 evolved 是同义词。故选A项。

3.推理判断题。根据最后一段第二句“not all durian species are edible, and some of them may even cause dam6.age to our health,可知，并不是所有的榴莲都是能吃的，有些榴莲是不可以吃的。由此可推断出C项是正确的。

4.主旨大意题。文章说榴莲可能是世界上最臭的水果，但没有人知道原因。新加坡的研究者决定来查明原因。最后通过绘制的榴莲基因图发现了它难闻气味的原因。由此可知，本文最好的题目应该是“榴莲难闻之谜”最为适合，故选D项。