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问题 单项选择题

对畸形中央尖的描述，不正确的是（）。

A．圆锥形中央尖萌出后不久与对颌牙接触，可致折断，使牙髓感染坏死，影响根尖发育

B．中央尖折断或磨损后，临床上表现为圆形或椭圆形黑环，中央有浅黄色或褐色的牙本质轴

C．牙本质轴中央有时可见黑色小点，此点即髓角，可用探针探入

D．无髓角深入型牙髓常有活力，牙根可继续发育

E．多位于面中央窝处，常对称性发生

答案

参考答案：C

阅读理解

根据短文内容，完成下面的任务。

Mrs. Smith is in a store. She looks for a school bag for her 7-year-old son. The clerk shows her a yellow one, but she says her son does not like the color. Then the clerk shows her a brown one.  (1) She says her son likes the color, but it is too small. The clerk says they will have some big ones next week.  (2) _tells, Mrs. Smith, her, telephone, number, the, clerk. She asks the clerk to call her when the big brown school bags are in the store. Mrs. Smith says goodbye to the clerk and then goes home.

任务一、回答下列问题。

小题1:What does Mrs. Smith want to buy?

小题2:Why doesn’t Mrs. Smith buy the yellow one?

小题3:What does the clerk do when the big brown ones are in the store?

任务二、将短文中(1)处划线句子翻译成汉语。

小题4:_____________________________________________________________

任务三、将短文中(2)处的单词连接成一个意义完整的句子。

小题5:____________________________________________________________
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问答题 简答题

什么叫炉渣熔化性温度？它对高炉冶炼有什么影响？
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