全冠粘固后出现牙龈炎，其可能的原因，除了 A．轴壁突度不良 B_爱下问搜题

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问题单项选择题

全冠粘固后出现牙龈炎，其可能的原因，除了

A．轴壁突度不良
B．冠边缘过长
C．冠边缘不密合
D．龈沟内粘固剂残留
E．咬合早接触

答案

参考答案：E

完形填空

阅读下面短文, 掌握其大意, 然后从16 ~ 30各题所给的A、B、C和D项中，选出最佳选项, 并在答题卡上将该项涂黑。
Mrs. Jones was very fond of singing. She had a good   16 , except that some of her high notes tended to sound like a gate, which someone had forgotten to   17 . Mrs. Jones was very conscious of this   18 , and took every   19  she could find to practice these high   20 . As she lived in a small house where she could not practice without   21   the rest of the family, she usually went for long walks along the country roads whenever she had time, and practiced her high notes there. Every time she heard a   22  or a person coming along the   23 , she stopped and   24   until she could no longer be heard before she started practicing again, because she was a   25  person, and because she was sensitive about those high notes.
One afternoon, however, a fast, open car came up behind her so   26  and so fast that she did not hear it until it was only a few yards from her. She was singing some of her highest and most   27  notes at the time, and as the car passed her, she saw an anxious   28   suddenly come over its driver’s face. He put his brakes on violently, and as soon as the car stopped, jumped out and began to   29  all his tires carefully.
Mrs. Jones did not dare to tell him what the noise he had heard had really been, so he got back into his car and drove off as   30  as he had been when he stopped.

B．explanation

多项选择题

吸附塔系统停车时，旋转阀旁路（吸附塔进出料旁路的）的作用是（）。

A、便于控制精馏系统平稳停车

B、便于控制吸附塔压力

C、便于精馏塔系统的物料平衡

D、便于对吸附塔床层进行退料