题目

如图是一株美丽的勾股树，其中所有的四边形都是正方形，所有的三角形都是直角三角形。若正方形的A、B、C、D的边长是3、5、2、3，则最大正方形E的面积是    ．   答案：【答案】47【解析】设中间两个正方形的边长分别为x、y，最大正方形E的边长为z，则由勾股定理得：x2=32+52=34；y2=22+32=13；z2=x2+y2=47；即最大正方形E的边长为： ，所以面积为：z2=47．设中间两个正方形的边长分别为x、y，最大正方形E的边长为z，则由勾股定理可得z2=x2+y2，则最大正方形E的面积为z2。     One kind of female butterfly mates only once in its life —and then closes its wings to avoid "harassment" when pursued by persistent and unwanted males, a Japanese researcher said.     Observations of the Small Copper Butterfly, a colourful orange and black butterfly, showed that some females closed their wings when males flew by, but only when they were males of their own species, said Jun-Ya Ide, an associate professor at Kurume Institute of Technology in Fukuoka, western Japan.     "When we looked into why, the males were courting the females. They do this very stubbornly, so the females sometimes try to get away-or prefer to stay unobserved," he added.     Ide and his colleagues brought a model of a male butterfly near the females to test their reactions and found that young females that had yet to mate kept their wings open, but those that had already mated closed them.     Not only can the persistent attentions of unwanted suitors harm the delicate females, fleeing from them —with the male often in pursuit —uses up strength and can even shorten their lives, he added.     "Closing their wings makes them less visible, helping them avoid communication with their own species. We figured they were trying to avoid harassment by males," Ide said.1. What does the word "harassment" mean in the paragraph?A. sexual invasion   B. embarassment  C. attack  D. threat 2. Why some some females closed their wings when males flew by?A. because the female butterfly mates only once in its life. B. because they close their wings to avoid "harassment" when pursued by persistent and unwanted males.C. because they don’t like the male butterfly at all.D. because they are afraid of the male butterfly.3. According the the passage, which is correct?A. The females closed their wings when males flew by.B. The female butterfly mates only once in its life.C. Only the model of a male butterfly can make the young female butterflies to keep their wings open.D. Not only can the persistent attentions of wanted suitors harm the delicate females, fleeing from them —with the male often in pursuit -- uses up strength and can even shorten their lives.