4．Dolphins have been declared the world's second most intelligent creatures after humans，with scientists suggesting they are so bright that they should be treated as"non-human persons"．
Studies into dolphin behavior have highlighted how similar their communications are to those of humans and that they are brighter than chimpanzees．These have been backed up by anatomical （解剖学） research showing that dolphin brains have many key features associated with high intelligence．Recently，a series of behavioral studies has suggested that dolphins，especially species such as the bottlenose，whose brains weigh about 5lb，could even be brighter than chimps，which some studies have found can reach the intelligence levels of three-year-old children．The studies show how dolphins have distinct personalities，a strong sense of self and can think about the future．
It has also become clear that dolphins are"culture"animals，meaning that new types of behavior can quickly be picked up by one dolphin from another．In one study，Diana Reiss，professor of psychology at Hunter College，City University of New York，showed that bottlenose dolphins could recognize themselves in a mirror and use it to inspect various parts of their bodies，an ability that had been thought limited to humans and great apes．In another，she found that they also had the ability to learn an elementary symbol-based language．
Other research has shown dolphins can solve difficult problems，while those living in the wild cooperate in ways that imply complex social structures and a high level of emotions．In one recent case，a dolphin rescued from the wild was taught to tail-walk for three weeks in a dolphinarium （海豚宫） in Australia．After she was released，scientists were astonished to see the trick spreading among wild dolphins who had learnt it from the former captive （被俘的）．Such observations have prompted questions about the brain structures of dolphins．
Researchers have found that brain size varies hugely from around 7oz for the small species to more than 19lb for the sperm whales，whose brains are the largest on the planet．Human brains，by contrast，range from 21lb-4lb．When it comes to intelligence，however，brain size is less important than its size relative to the body．
oz：an ounce in weight （1oz=28g）
lb：a pound in weight （1lb=454g=16oz）
（Note：Answer the questions or complete the statements in no more than twelve words．）
78．The which in the 2nd paragraph refers tochimps．
79．What do bottlenose dolphins do to make Diana Reiss believe they are"culture"animalsInspecting various parts of their bodies and learning an elementary symbol-based language．
Inspecting their bodies and learning a symbol-based language．？
80．The spreading of tail-walk shows wild dolphins havecomplex social structures and a high level of emotions．．
81．What is the main factor that decides the level of intelligence according to the last paragraphThe brain size relative to the body．？
分析 本文主要介绍了海豚的生活习性以及学习语言、彼此间相互学习等基本能力的介绍，包括大脑在其发育过程中的重要作用等．
解答 78．chimps
在这句话中which引导了一个定语从句，关系词which代替先行词chimps，所以它指的是chimps．
79．Inspecting various parts of their bodies and learning an elementary symbol-based language．
Inspecting their bodies and learning a symbol-based language．
根据第三段中的"In one study，Diana Reiss，professor of psychology at Hunter College，City University of New York，showed that bottlenose dolphins could recognize themselves in a mirror and use it to inspect various parts of their bodies"以及"In another，she found that they also had the ability to learn an elementary symbol-based language．"可知，Diana Reiss教授在研究中发现海豚可以在镜子中认出自己，并利用镜子来检查自己的身体部位，而且海豚还有学习以符号为基础的语言的能力．
80．complex social structures and a high level of emotions．
根据第四段中的"Other research has shown dolphins can solve difficult problems，while those living in the wild cooperate in ways that imply complex social structures and a high level of emotions．"可知，野生海豚拥有复杂的社会体系和高水平的情绪，而下文所举的"tail-walk"传播的例子正说明了这一点．
81．The brain size relative to the body．
根据最后一段中的"When it comes to intelligence，however，brain size is less important than its size relative to the body．"可知，大脑与身体的比例是决定智力的重要因素．
点评 本文是科普知识类的阅读表达，要求学生在阅读理解的基础上，根据短文后的题目，在文中找到相关的内容，并用简洁、准确的句子，将理解的内容，书面表达出来．做题时，注意表达的内容不要超出规定的字数．
