题目

如图，⊙O是△ABC的外接圆，BC是⊙O的直径，D是劣弧中点，BD交AC于点E.  ⑴求证：AD2=DE·DB⑵若BC=13，CD=5，求DE的长  答案：        解析:略 One Saturday afternoon, a six-year-old girl went for a walk. She crossed a large area of grassland into the woods __36__ she realized that she was lost. Sitting on a rock and __37__ what to do, she began crying. After a while. she__38__ to walk along a wide path lined with tall trees and thick bushes. __39__ it was getting dark, she saw a small, dark wooden house. She opened the door and __40__ stepped in. Suddenly, she heard a strange noise, and she ran out the door and back to the __41__. Cold and tired, she fell asleep near a __42__. The girl’s parents were out and her dog, Laddy, was at home. Laddy __43__ that his mistress was in danger. He jumped __44__ a window, breaking the glass. He looked in the fields. But he couldn’t find his mistress anywhere. However, from the ground came a __45__ scent (气味) as he lowered his head. He __46__ the scent and walked across the grassland. Barking __47__ into the air, the dog __48__ through the woods until he found the __49__ . But the girl was not there, so he headed back to the woods. Much to his __50__ , he saw his mistress’ blue shirt in the distance. He __51__ over some bushes and saw the little stream, where the girl was __52__.When she opened her eyes and    53   her dog standing beside her, the girl said, “you   54  me, Laddy,” and she kissed him several times. Seeing their daughter and dog coming back, the parents burst into tears of    55   . That night Laddy had a hero’s supper: a huge meal of steak 1. A．since B．while C．before D．as 2. A．wondering B．forgetting C．remembering D．regretting 3. A．preferred B．expected C．failed D．decided 4. A．Because B．When C．If D．Until 5. A．hopelessly B．carelessly C．cautiously D．unwillingly 6.A. trees               B. woods          C grasses.        D. bushes 7. A．stream B．rock C．tree D．house 8. A．heard B．found C．sensed D．smelt 9. A．at B．in C．onto D．through 10. A．familiar B．strange C．terrible D．Pleasant 11. A．missed B．discovered C．followed D．ignored 12. A．calmly B．merrily C．gently D．loudly 13. A．wandered B．looked C．searched D．traveled 14. A．girl B．house C．window D．hero 15. A．satisfaction B．disappointment C．embarrassment D．delight 16. A．jumped B．climbed C．walked D．flew 17. A．awake B．asleep C．abandoned D．available 18. A．saw B．spotted C．observed D．watched 19. A．disturbed B．comforted C．rescued D．scared 20. A．pain B．shock C．sorrow D．relief