Question

3．The discovery of an ancient giant panda skull has confirmed its bamboo diet dates back more than 2 million years and may have played a key part in its survival．
A  Chinese-US research team reports its results today following studies on a fossil skull found in south China's Cuangxi Zhuang Autonomous Region in 2001．
The six fossils unearthed in Jinyin Cave are dated between 2.4 and 2 million years ago，according to the report in Proceedings of the National Academy of Sciences，an influential US journal．
Jin Changzhu，of the chinese Academy of Sciences （CAS） and lead author of the paper，said the smaller fossil skull indicates the giant pandas were about a third smaller than today's pandas．
Researchers knew the panda reached its maximum size about 500，000 years ago，when it peaked，and then gradually became smaller．
Jin，a paleontologist （古生物學(xué)者） at the Institute of Vertebrate paleontology and Paleoanthropology （古人類學(xué)） attached to the CAS，said the size variation was a basic rule of evolution．
"A species tends to grow bigger when it reaches the peak of its population，but becomes smaller when numbers decline，"he said．
The dental remains of the skull，which is the oldest giant panda skull ever found，are similar to today's pandas，indicating the type of teeth that could munch （津津有味地嚼）mountains of bamboo．A panda can eat up to 40kg of bamboo per day．
Paleoanthropologist Russell Ciochon，the US co-author at the University of lowa，said the panda's focus on bamboo could have helped it survive all these years．
"Once an animal begins to rely on a common and stable food source，such as bamboo，it tends to evolve a larger body size，"he said．"As individuals of the evolving species grow bigger，they have a better chance not to be eaten by predators （肉食動(dòng)物） due to their larger body size．"
33．According to the research of the CAS，there were most pandas in the worldC．
A.2 million years ago
B．between 2.4 and 2 million years ago
C.500，000 years ago
D．Nowadays
34．The underlined word"variation"in para 6 meansB．
A．fall           B．change       C．increase       D．decrease
35．From the passage，we can learnB．
A．pandas began to eat bamboo 2 million years ago
B．a(chǎn) species tends to grow smaller when numbers decline
C．the giant pandas were about a third the size of today's pandas
D．pandas'bamboo has played an important role in its development．

Answer 1

分析 古代大熊貓頭骨的發(fā)現(xiàn)證實(shí)了大熊貓吃竹子飲食習(xí)慣可追溯到200萬(wàn)多年，這可能是影響其生存的一個(gè)關(guān)鍵部分．

解答 33．C．事實(shí)細(xì)節(jié)題．根據(jù)短文Researchers knew the panda reached its maximum size about 500，000 years ago，when it peaked，and then gradually became smaller．可知500，000年以前的大熊貓數(shù)量是最多的，故選C．
34．B．詞義猜測(cè)題．根據(jù)下文"A species tends to grow bigger when it reaches the peak of its population，but becomes smaller when numbers decline，"he said．可知，一個(gè)物種的數(shù)量達(dá)到頂峰，它們的體型會(huì)變大，數(shù)量減少，體積會(huì)變小，所以是體型的改變，故選B．
35．B．事實(shí)細(xì)節(jié)題．根據(jù)短文"A species tends to grow bigger when it reaches the peak of its population，but becomes smaller when numbers decline，"he said．可知當(dāng)一個(gè)物種數(shù)量減少時(shí)，這個(gè)物種的生物的體型會(huì)變小，故選B．

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