设想一下三条鱼成群而游。一条鱼可能被捕食者Y看到的空间是以该鱼为圆心，Y能看到的最远距离为半径的圆。当Y在这三个圆之中的一个时，该鱼群可能受到攻击。由于三条鱼的鱼群之间距离很近，这三个圆在很大程度上重叠在一起。
下面哪一项是从上面一段中得出的结论( )
A．捕食者攻击四条鱼的鱼群的可能性比攻击三条鱼的鱼群的可能性小
B．整个鱼群的易受攻击性比鱼群中的每一条鱼的易受攻击性大不了多少
C．一条鱼能被看见的最大距离不怎么取决于鱼的大小，而更多地取决于该鱼是否成群地游动
D．如果捕食者Y本身游在一群Y之中，则Y能看到其他猎物的最大距离有所增加
参考答案：B
阅读下面短文，掌握其大意，从短文后各题所给的四个选项（A、B、、C、D)中，选出可以填入空白处的最佳选项。 My first memories of acts of kindness are from when I was about 12 years old. From then on I always 36 at home and with friends. That winter I notice that many 37 people had difficulty getting to the 38 store after a snowstorm. So I started to spend part of a 39 Saturday knocking at apartment doors to ask if any one needed 40 from the store. The grocery store was down a huge hill and I would bring 41 a couple of bags of groceries for them. I liked it and it made them so 42 . It started with 43 alone and then the number grew. A short time later, my 44 in the building asked what I was doing and a couple of them 45 and it became a routine. I 46 asked for or took money for it. Sometimes the ladies 47 slip the change in my pocket. I would just buy something the next time to give to them, 48 flowers or a card. I did this every 49_ up to when I left to go to college. When I was away at 50 , many people asked my mom how I was doing. Through those conversations she 51 what I used to do -—I had never told her. Now, I’m a teacher and teaching my students the art of true 52 ; Everyone in the world needs help, and everyone can also 53 help. The image of those old people’s happiness caused by my 54 of goodwill appears in my mind every time I have the chance to do something 55 . This is the power of charity.
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