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问题 解答题

一根圆柱，把它截成9个小圆柱所得的表面积总和，比截成6个小圆柱所得的表面积总和多180平方厘米，原来圆柱的底面积是多少平方厘米？

答案

因为截成9个小圆柱所得的表面积总和，比截成6个小圆柱所得的表面积总和多180平方厘米，

所以6个底面积的和是180平方厘米，

所以原来圆柱的底面积是：180÷6=30（平方厘米），

答：原来圆柱的底面积是30平方厘米．

选择题

对于SO2、CO2、MnO2三种化合物的说法正确的是（　　）

A．都含有氧分子

B．都含有二个氧原子

C．都含有氧元素

D．都属于混合物
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单项选择题

Research on animal intelligence always makes me wonder just how smart humans are. (91) the fruitfly experiments described in Carl Zimmer’s piece in the Science Times on Tuesday. Fruit flies who were taught to be smarter than the average fruit fly (92) to live shorter lives. This suggests that (93) bulbs burn longer, that there is an (94) in not being too terrifically bright.
Intelligence, it (95) , is a high-priced option. It takes more upkeep, burns more fuel and is slow (96) the starting line because it depends on learning—a gradual (97) —instead of instinct. Plenty of other species are able to learn, and one of the things they’ve apparently learned is when to (98) .
Is there an adaptive value to (99) intelligence That’s the question behind this new research. I like it. Instead of casting a wistful glance (100) at all the species we’ve left in the dust I.Q. wise, it implicitly asks what the real (101) of our own intelligence might be. This is (102) the mind of every animal I’ve ever met.
Research on animal intelligence also makes me wonder what experiments animals would (103) on humans if they had the chance. Every cat with an owner, (104) , is running a small-scale study in operant conditioning, we believe that (105) animals ran the labs, they would test us to (106) the limits of our patience, our faithfulness, our memory for terrain. They would try to decide what intelligence in humans is really (107) , not merely how much of it there is. (108) , they would hope to study a (109) question. Are humans actually aware of the world they live in (110) the results are inconclusive.

A．upward

B．forward

C．afterward

D．backward
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