患者女，60岁，戴上颌活动义齿1个多星期，出现上唇牵拉疼痛，右侧常有咬颊黏膜，且出现恶心、呕吐现象。检查：
缺失，已行可摘局部义齿修复，义齿固位稳定良好，上颌颊黏膜转折处可见2～3mm大小的溃疡面，右侧颊黏膜见2mm大小的血肿，下颌为双侧游离端义齿，侧向咬合时，工作侧出现早接触，余无异常。
上颌颊黏膜出现牵拉疼痛的原因是（）
A.印模不精确
B.颊黏膜转折处缓冲不足
C.颊黏膜转折处缓冲过多
D.颊黏膜转折处基托边缘过短
E.颊黏膜转折处基托不密合
参考答案：B
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| Even though it was only October, my students were already whispering about Christmas plans. With each passing day everyone became more 1 wthting for the final school bell. Upon its 2 everyone would run for their coats and go home, everyone except David. David was a small boy in ragged clothes. I had often 3 what kind of home life David had, and what kind of mother could send her son to school dressed so 4 for the cold winter months, without a coat, boots, or gloves. But something made David 5 . I can still remember he was always 6 a smile and willing to help. He always 7 after school to straighten chairs and mop the floor. We never talked much. He 8 just smile and ask what else he could do, then thank me for letting him stay and slowly 9 home. Weeks passed and the 10 ovre the coming Christmas grew into restlessness until the last day of 11 before the holiday break. I smiled in 12 as the last of them hurried out the door. Turning around I saw David 13 standing by my desk. "I have something for you" he said 14 from behind his back a small box. 15 it to me, he said anxiously. "Open it" I took the box from him, thanked him and slowly unwrapped it. I lift the lid and to my 16 saw nothing. I looked at David's smiling face add back into the box and said. "The box is nice, David, but it's 17 ." "Oh no it isn't" said David "It's full of love, my mum told me before she died that love was something you couldn't see or touch unless you know it's there." Tears filled my eyes 18 Iooked at the proud dirty race that I had rarely given 19 to. After that Christmas, David and I became good friends and I never forgot the meaning 20 the little empty box set on my desk. | ||||
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