听力原文:W:What present would you like to give your wife for her birthday?
M:I haven't decided yet. But I'd like to buy her something special.
Q:Why does the man want to buy a present for his wife?
(9)
A.For Christmas Day.
B.For Mother's Day.
C.For his wife's birthday.
D.For Father's Day.
第1题
制动轮发热,摩擦片发出焦味并且磨损很快的原因下列叙述不正确的是:()
A.闸瓦在松闸后,没有均匀的和制动轮完全脱开,因而产生磨擦;
B.两闸瓦与制动轮间隙不均匀,或者间隙过大;
C.制动器弹簧张力过大;
D.制动轮工作表面粗糙
第4题
桥式起重机“吊钩组坠落”的现象,引起的可能原因有()。
A.制动瓦衬与制动轮间隙不均匀,在机构运行时,瓦衬仍在制动轮上,磨擦生热冒烟
B.制动轮直径不圆度超差
C.制动轮和减速器输入轴不同心
D.严重超载或钢丝严重损坏
第5题
A.车轮轮缘磨损严重
B.制动瓦衬与制动轮间隙不均匀,在机构运转时,瓦衬仍压在制动轮上,摩擦生热冒烟
C.辅助弹簧失效,推不开制动臂,瓦衬始终压在制动轮上
D.制动轮表面粗糙
E.电源未接通
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