问题
单项选择题 A1/A2型题
牙石引起牙龈炎症的主要致病作用是（）
A.牙石对牙龈有机械刺激
B.牙石的多孔结构容易吸附大量的细菌毒素
C.牙石表面常可以形成未矿化的菌斑，刺激牙龈造成炎症
D.龈下牙石可促进龈沟液的渗出增加
E.牙石妨碍日常口腔卫生措施的实施
答案
参考答案：C
搜题请搜索小程序“爱下问搜题”
牙石引起牙龈炎症的主要致病作用是（）
A.牙石对牙龈有机械刺激
B.牙石的多孔结构容易吸附大量的细菌毒素
C.牙石表面常可以形成未矿化的菌斑，刺激牙龈造成炎症
D.龈下牙石可促进龈沟液的渗出增加
E.牙石妨碍日常口腔卫生措施的实施
参考答案：C
While waiting to pick up a friend at the airport in Portland, Oregon, I noticed a man coming toward me carrying two light bags. He stopped right next to me to his family. First he moved to his youngest son as he laid down his bags. They gave each other a long, loving hug. they separated, I heard the father say, “It’s so good to see you, son. I missed you so much!” His son smiled somewhat shyly and replied softly, “Me, too, Dad!” Then the man stood up, gazed in the of his oldest son and said, “You’re already quite the young man. I love you very much, Zach!” They too hugged a most loving, tender hug. After several , he turned to his wife and declared, “I’ve saved the best for last!” and to give his wife the longest, most passionate kiss I remember seeing. For an instant they me of newlyweds(新婚夫妇), but I knew by the age of their kids that they couldn’t possibly be. I puzzled about it for a moment and gathered my courage to ask, “Wow! How long have you been married?” “Almost twelve years.” he replied, breaking his gaze from his lovely wife’s face. “Well then, how long have you been away?” I asked. The man turned and looked at me,. “Two whole days” Two days? I was . By the intensity of the greeting, I had he’d been gone for at least several weeks — if not months. I know my expression me. Hoping to stop our conversation politely and continue with my for my friend, I said almost immediately, “I hope my is still that passionate after twelve years!” The man suddenly smiling. He looked me straight in the eye, and with power that burned right into my soul, he told me something that left me a person. He told me, “Don’t , friend …decide!” Then with wonderful smile, he and his family turned and left together. I was still watching that special family walk just out of sight when my friend to me and asked, “What are you looking at?” Without , and with a curious sense of certainty, I replied, “ My future!”
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