The bristlecone pine is the longest-living thing on the earth. These trees, with their strangely-shaped, wind-beaten limbs(枝干), can live up to 5,000 years. But experts worry that a warming climate in some areas may threaten its future.
Researchers say warmer weather is permitting a similar kind of tree, the limber pine, to take over good growing places from the ancient bristlecone. They say the tree is being crowded out of mountainous areas where it grows.
“The bristlecone pine is the oldest individually growing organism,” researchers say. They grow in high mountain forests in eastern California, Nevada and Utah. In those mountains, the trees face high winds and extreme temperatures, which leave them with twisted limbs and shapes. “Even in such tough conditions,” Brian Smithers, a researcher at the University of California, said, “the limber pine is taking all the good spots.”
The limber pine is the bristlecone’s distant relative and competitor. It can also live a long time——up to 2,000 years. And it is usually found at lower altitudes, where temperatures are warmer. However, according to a three-year study which centered on trees that have started growing in the last 50 years in California’s White Mountains, most of the trees growing at higher altitudes were limber pines.
Scientists compared the competing species to two o1d men in a very slow race up a mountainside. This race between such slow-growing trees takes thousands of years. They say climate change is causing the competition.
Smithers said the bristlecone pines are not in danger of disappearing. But he assumes they could be crowded out of some places where they have grown for thousands of years.
The researchers say the findings show how climate change can affect the two kinds of trees. The information, they say, can help scientists understand more complex forests.
89．What’s the function of Paragraph 1?
A．To introduce a topic. B．To summarize the whole passage.
C．To describe the appearance of a tree. D．To praise the hard work of the experts.
90．What does the underlined sentence in Paragraph 2 mean?
A．There will be older trees sent out of those mountains.
B．There will be more places covered with bristlecone pines.
C．There will be better limber pines replacing the ancient ones.
D．There will be fewer bristlecone pines growing in those areas.
91．According to the passage, the reason why limber pines can grow at higher altitudes is_________.
A．the high winds B．the difficult conditions
C．the changing climate D．the extreme temperatures
92．What is the researchers’ attitude towards the future of the bristlecone pine?
A．Positive. B．Concerned.
C．Enthusiastic. D．Indifferent.
89．A
90．D
91．C
92．B
【分析】
这是一篇说明文。科学家的一项研究发现：气候变暖使得柔枝松渐抢占了狐尾松的生长地。
89．推理判断题。由第一段内容可知，狐尾松是在地球上生活最长久的植物，它具有奇怪的外形，被风吹歪的树干，它可以活5000年。但是专家担心一些地区的气候变暖可能会威胁它的未来。由此可知，第一段的作用是引出话题。故A选项正确。
90．词义猜测题。由划线句子前面的the limber pine，to take over good growing places from the ancient bristlecone可知，柔枝松渐抢占了狐尾松的生长地。因此，划线句子的意思就很明确了，狐尾松正在被挤出它们生长的山区，将会有更少的狐尾松在这里生长。故D选项正确。
91．细节理解题。由第五段This race between such slow-growing trees takes thousands of years．They say climate change is causing the competition和倒数第一段中的The researchers say the findings show how climate change can affect the two kinds of trees可知，天气变化影响树木，导致了树木之间的竞争，竞争过程对于生长缓慢的树木来说会持续几千年。故C选项正确。
92．观点态度题。由整个短文可知，气候变暖使得柔枝松渐抢占了狐尾松的生长地。狐尾松生活在更高海拔的地区。Smithers认为狐尾松没有处于灭绝的境地，但几千年以后有可能被挤出生存地区。这些发现能够表明气候变暖对树木的影响，可以帮助科学家明白更加复杂的森林。故B选项正确。