火灾的主要助燃物是什么？
参考答案：
空气（氧）。
—What do you think of their school?
—It's really beautiful. But I don't think their school is as big as _____. [ ]
A. ours
B. us
C. we
D. our
患者男，52岁，鼻咽癌放疗术后1年，因多个牙冷热刺激痛就诊，查体：缺失，残根，颈缘环状龋
患者治疗方法及预防方法（）
A.人工唾液含漱
B.氟水漱口
C.定期检查
D.去除菌斑
E.以上皆是
颈缘环状龋