题目

如图，E、F是正方形ABCD的边AD上的两个动点，满足AE=DF．连接CF交BD于G，连接BE交AG于H．已知正方形ABCD的边长为4cm，解决下列问题：（1）求证：BE⊥AG；（2）求线段DH的长度的最小值． 答案：【答案】（1）见解析；(2)2-2．.【解析】（1）根据正方形的性质可得AB=AD=CD，∠BAD=∠CDA，∠ADG=∠CDG，然后利用“边角边”证明△ABE和△DCF全等，根据全等三角形对应角相等可得∠1=∠2，利用“边角边”证明△ADG和△CDG全等，根据全等三角形对应角相等可得∠2=∠3，从而得到∠1=∠3，然后求出∠AHB=90°，10．听短文，选择正确答案．短文读两遍．21．What did Mrs．Brown want to buy？A．A coat．B．A pair of jeans．C．A sweater．22．Why didn't Mrs．Brown buy it at once？A．Because she didn't like the color．B．Because she was busy．C．Because she didn't have enough money．23．Why didn't her husband want her to buy it？A．Because it was too expensive．B．Because she had so many sweaters．C．Because it was not good enough．24．When did her husband agree to buy it？A．The next day．B．The third day．C．After a week．25．Who bought the sweater at last？A．Mrs．Brown．B．Mr．Brown．C．Nobody．