This November, a hundred million butterflies will drop from the sky over Mexico, like autumn leaves. But for how long? Genetically modified maize (玉米) could mean extinction for this beautiful butterfly, Rafael Ruiz reports.
Although its body is about 3cm long and it only weighs 1 gin, the Monarch butterfly manages to travel 5,000km each year. It seems to be so fragile, but its long journeys are proof of its amazing ability to survive. This autumn, the Monarch butterfly will once more set out on its journey from the US. It will keep going until it reaches Mexico. It travels these huge distances to escape the cold weather in the north.
In November, millions of Monarchs fall like bright, golden rain onto the forests in the mountains of central Mexico. In the silence of these mountains you can hear a strange flapping (拍动) of wings, as the Monarchs arrive at their destination. In the mountains, which reach a height of 3,000 metres, the butterflies are safe.
Before reaching their journey"s end they have faced strong winds, rain and snowstorms and they do not all manage to reach their destination. When the winters are really bad, perhaps 70 percent of them will not survive. Their long journey to Mexico is thought to be one of the most amazing events in the whole of the American continent. When they get there they will stay until the beginning of April, when their internal calendar tells them that it is time to go back. The long journey, with all its dangers, begins again.
These delicate creatures now face danger of another kind—from scientific progress. In the US, millions of farms grow genetically modified maize which is pure poison for the butterfly. Laboratory experiments have shown that half of the butterflies which feed on the leaves of genetically modified maize die within 48 hours. Not all experts agree that this variety of maize is responsible for the threat to the Monarchs. In spite of these doubts, the European Union has refused to approve new crops of genetically modified maize until further investigations have been carried out.
Greenpeace is campaigning against genetically modified products (in Spain, there are already 20,000 hectares of modified maize). The environmental organization recently published a list of 100 species of butterfly in Europe alone which are threatened with extinction.
单选题
The Monarch butterfly travels 5,000km each year.
【正确答案】
A
【答案解析】[解析] 由题干中关键词Monarch butterfly和5,000km可定位至第二段第一句。该句“the Monarch butterfly manages to travel 5,000km each year”中的manage to意思为“成功做到……”，和本题中表述相符。故选A。
单选题
The Monarch butterfly looks fragile.
【正确答案】
A
【答案解析】[解析] 由题干中关键词looks fragile可定位至第二段第二句。该句明确说到，“It seems to be so fragile...”，这里的it指代的就是前文中所说的Monarch butterfly，而seems to和题干中的looks意思相同。题干表述是对原文的同义转换，故选A。