题目

如图，在Rt△ABC中，∠BAC=90°，AC=2AB，点D是AC的中点．将一块锐角为45°的直角三角板如图放置，使三角板斜边的两个端点分别与A、D重合，连接BE、EC．试猜想线段BE和EC的数量及位置关系，并证明你的猜想．       答案：数量关系为：BE=EC，位置关系是：BE⊥EC．证明：∵△AED是直角三角形，∠AED=90°，且有一个锐角是45°，∴∠EAD=∠EDA=45°，∴AE=DE，∵∠BAC=90°，∴∠EAB=∠EAD+∠BAC=90°+45°=135°，∠EDC=∠ADC-∠EDA=180°-45°=135°，∴∠EAB=∠EDC，∵D是AC的中点，∴AD= AB，∵AC=2AB，∴AB=DC，∴△EAB≌△EDC，∴EB=EC，且∠AEB=∠AED=90°，用方框中所给单词的适当形式填空，使短文完整正确（每个单词限用一次.每空只填一个单词）。The weekend is here! You can sleep longer and get up later than usual. But is it a good thing to sleep longer during weekends?【1】 from the United States said this habit is bad for your health and can make you gain weight(增加体重),CNN reported.According to sleep expert (专家）Vsevolod Polotsky, sleeping longer during weekends【2】not good for you. You might feel like you’re catching up on sleep. But if you still sleep poorly during weekdays, you will feel hungry more often. You might 【3】 more and gain some weight.Also, sleeping more during weekends can change 【4】biological clock (生物钟)。 If you get up late on the weekend, you might eat breakfast, lunch and dinner later than usual. Eating later in the day also 【5】you to gain weight.Tips for better sleep.Keeping your 【6】warm can help you sleep. Put on a pair of socks before 67 【7】to bed.This can help you 【8】asleep faster.Exercising regularly can help you sleep 【9】.Keep your bedroom as 【10】as possible.