．水是生命之源，节约用水，从点滴做起。下列关于水的理解正确的是
A．0℃的水内能为零
B．水温降低，内能一定减小
C．水受热时，体积变大、密度变大
D．30℃的水比20℃的水所含的热量多
答案：B
一切物体在任何温度都有内能，A错；内能与物体的温度有关，温度越高，内能越大，B正确；水的密度比冰的密度大，所以水结冰时，体积变大，密度变小，C错；热量指的是由于温差的存在而导致的能量转化过程中所转移的能量，而不能说物体含有多少内能，D错。故选B。
Don’t shoot butterflies with guns. Can you 36 someone running after a butterfly with a gun in his hands? Won’t such stupidity make you burst out laughing? But wait. Stop and consider how often you might have done something 37 . A hen, Henny-Penny, lived in a forest with many other animals and birds. One fine, sunny morning, she was busy looking for 38 in the ground. Suddenly she let out a frightened cackle (咯咯叫) with wings flapping 39 . A dry leaf had fallen down on her, and she went 40 at whoever she met, “Run, run for your lives; the sky is falling.” The other creatures stopped whatever they were doing. Some ran behind Henny-Penny, screaming warnings with her, while others 41 the unfounded story that the sky was falling. We all have 42 people like this hen. The rest of us are like the other foolish creatures who didn’t stop to verify (证实) the 43 for themselves. They shoot butterflies with guns. They just will not think for themselves. Why don’t people think for themselves? Often because of laziness, or because they don’t want to be 44 for their way of thinking. Walking through life 45 is more dangerous than crossing a busy road with eyes closed. Our thoughts should lead us towards the light of wisdom and sense. Our thinking should be high, 46 us to the ranks of the sensible. We have been blessed with reasoning, sensitive minds. Let us make use of them and be 47 of our own minds. Don’t let your mind be enslaved by someone else. Stop, think and then go ahead. 小题1:.
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