19．A.lost B．chose

　　C．left D．quit

　　答案：C　由常识可知，退休就是离开工作岗位，即leave，而非 quit“辞职，退出”；lose“失去”；choose“选择”。

　　20．A.pets B．toys

　　C．friendsD．colleagues

　　答案：B　 就像一月份的孩子一样，他们又去寻找新的玩具了。这与上文相呼应。上文提到，圣诞过后，孩子很快就对圣诞玩具不感兴趣了。

　　.阅读理解

　　Most of the more than 6,000 species of frogs in the world lay their eggs in water. But many tropical (热带的) frogs lay their eggs out of water. This behavior protects the eggs from aquatic predators, such as fish and tadpoles, but also increases their risk of drying out. Justin Touchon, post­doctoral fellow at the Smithsonian Tropical Research Institute, discovered that climate change in Panama may be changing frogs' course of evolution (进化). By analyzing long­term rainfall data collected by the Panama Canal Authority, Touchon discovered that rainfall patterns are changing just as climate­change modds predict.

　　“Over the past four decades, rainfall has become much less during the wet season，” said Touchon. “The number of rainy days decreased, and the number of gaps between storms increased.”

　　The eggs of the pantless treefrog, Dendropsophus ebraeeatus, are extremely susceptible to drying. The embryos die within a day when there is no rain. Heavy rains trigger breeding(繁殖), so as storms become sporadic, the chance of rain within a day of being laid decrease and so does egg survival.

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