例2 如图所示,在△ABC和△DCB中,AB=DC,要使△ABO≌△DCO,请你补充条件_____________(只要填写一个你认为合适的条件).
解题思路:由AB=DC以及图形隐含的对顶角相等:∠AOB=∠DOC可知,要使△ABO≌△DCO,根据(AAS)识别法,直接可补充∠A=∠D或∠ABO=∠DCO.间接可补充:AC=DB.
评注:本题是一道结论开放性试题,由于全等三角形的识别方法有(SSS)(SAS)(ASA)(AAS)和直角三角形的(HL)识别法,因此,这类题目具有答案不唯一的特点.在添加条件时,要结合图形,挖掘隐含的公共边、公共角、对顶角等条件.
例1 如图,在△ABC与△DEF中,给出以下六个条件中(1)AB=DE(2)BC=EF(3)AC=DF (4)∠A=∠D(5)∠B=∠E(6)∠C=∠F,以其中三个作为已知条件,不能判断△ABC与△DEF全等的是( )
A.(1)(5)(2) B.(1)(2)(3)
C.(4)(6)(1) D.(2)(3)(4)
解题思路:根据全等三角形的识别方法及给出的四个答案,一一加以辨别,因为用(SAS)识别法中,两边对应相等的话,一定要夹角对应相等,所以答案(D)不能判断△ABC与△DEF全等.
38. own 拥有,自己的 on one's own = by oneself
of one's own …自己所有的 I own a shop.
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版权所有:()
37. owe 欠 owe sb sth owe sth to sb I owed him $1,000
owe ... to ... 把…归功于 I owe my success to good luck. owing to = because of = due to 因为
36. overtake 赶上, 超过 overtake sb overtake a car
35. Game is over ! 结束 think over 仔细考虑 turn over = hand over 移交
overseas market 海外市场
34. output 产量,输出 Between 1932 and 1935, total output rose by 32 percent.
an output of 36 tons a day
33. outline 概述,画出…的轮廓 a detailed outline 详细的提纲
outline a map of the United States of American 勾画出…的轮廓
32. outcome 结果 The outcome of the match disappointed me.
30. other 其他的 each other = one another
on the other hand 另一方面 other than = except
take out 拿起 stay out 外出 cross out 划去 pull out 拨出 be tired out 精疲力竭 31. make out 辨别出 stand out 突出 give out 用完
out of date out of order out of work out of breath out of tune(走调)
out of question 毫无疑问;必定 out of the question 不可能
help sb out of pity 出于同情干… help sb out of kindness 出于好心干…
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