有关牙周袋的概念错误的是（）
A.牙周袋是病理性加深的龈沟
B.牙周袋包括假性牙周袋和真性牙周袋
C.真性牙周袋是指≥6mm的牙周袋
D.假性牙周袋因牙龈肿胀或增生所致
E.临床上的牙周袋包含龈缘向冠方迁移和沟底向根方延伸两种情况
参考答案：C
解析：真性牙周袋是指患牙周炎时，病变累及深层牙周组织，结合上皮的位置向根方增殖所形成的病理性加深的龈沟。
| 短文改错。 此题要求改正所有短文中的错误。对标有题号的每一行做出判断： 如有错误（每行只有一个错误），则按下列情况改正： 此行多一个词：把多余的词用斜线（\）划掉，在该行右边横线上写出该词，并也用 斜线划掉。 此行缺一个词：在缺词处加一个漏字符号（∧）,在该行右边横线上写出该加的词。 此行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。 注意：原行没有错的不要改。 | |
| It was a chance of a lifetime to win a first prize on the Story Writing Show. All I had to do was to write a story or present it. My teachers have been telling me how great my writing was. So if they had said was true, I would have a chance of winning the prize. What were better, I had useful help. There was Uncle Chen, gentleman living near my house, who was a very much famous writer He agreed to reading my story and give me some advices on how to write like a real writer | 1. _____ 2. _____ 4. _____ 5. _____ 6. _____ 7. _____ 8. _____ 9. _____ 10. _____ |