题目内容
Rising temperatures, rising sea levels and other trends are having an effect on the world's sea turtles. All female turtles come ashore at nesting beaches, dig nests in the sand,lay their eggs and then return to the sea. Erosion of nesting beaches caused by rising sea level and more intense storms adds the potential for further dangers to nesting beaches where people，dogs and rats already prey on the eggs of marine turtles.
Climate change directly affects the reproduction of sea turtles in three ways. First, sea level rise will affect significant nesting beach areas on low-level sand beaches such as Bonaire, the Maldives and the Great Barrier Reef. Second, rising temperatures increase the chance that sand temperature will exceed the upper limit for egg incubation(姅化) ，which is 34t. Third,rising temperatures bias(使偏向) the sex ratio toward females because temperature during incubation determines the sex of the egg. Loggerhead turtle nests in Florida are already producing 90 per?cent females owing to high temperatures，and if warming raises temperatures by an additional
or more,no males will be produced there.
Adult feeding patterns are also affected by climate change. Sea grass beds are in decline, water temperature is higher on inter-tidal sea grass fiats, and coral reefs, typically feeding grounds for green turtles, are affected by bleaching(漂白) .
Sea turtles have existed for more than 100 million years and have survived ice ages. As a result, they may be able to respond to unfavorable nesting temperatures, by seeking out new nesting sites. It may however take decades or centuries for sea turtles to re-establish and stabilize their habitats，and steady human development of coastal areas makes the availability of new hab?itat for them very limited.
( ) 1. What will happen if sand temperature is higher than 34^3?
A. More females will be born. B. Turtle eggs will not hatch.
C. Females will lay fewer eggs. D. Newly-born turtles will die.
( ) 2. In what way does climate change affect adult turtles?
A. They can't find enough food. B. They have lost their habitat.
C. Their feeding patterns are affected. D. Their living habits are changed.
( ) 3. What can we learn about Loggerhead turtle nests in Florida?
A. They already have an imbalanced sex ratio.
B.They can hardly survive the high temperature.
C.No more males are produced now.
D.Most of them die young.
( ) 4. We can infer from the last paragraph that______ .
A.human development constantly threaten the survival the of sea turtles
B.climate change can't threaten the survival of sea turtles
C.sea turtles can get used to cold climate
D.it's easy for sea turtles to find new habitat
1—4 BCAA
本文是说明文。气候变暖会导致海平面上升、气温升高，这一切都威胁着海龟的生存。1. B从文章第二段可知，海龟孵化的极限温度是34度，超过这个温度孵化就会失败。
2.C从文章第三段可知，气候变化影响了成年海龟的觅食模式。
3.A从文章第二段可知，温度升高，红海龟孵化的小海龟性别比例严重失衡。
4.A文章最后一段说明，海龟对气温变化适应能力很强，但人类的海岸开发对海龟是个很大的威胁。
B美国国家公园实际上是自然保护区。自美国黄石国家公园设立以来，全世界已有一百多个国家设立了多达1 ，200处风情各异、规模不等的国家公园。
