“白大衣综合征”

氟化物治疗牙本质过敏的作用机制是（）

A.堵塞牙本质小管，增加牙本质的硬度和抗酸，抗溶性

B.诱导修复性牙本质的形成

C.为蛋白沉淀剂，还原后沉积于牙本质小管堵塞小管

D.高热效应使牙本质表面变性和无机物熔融

E.刺激牙本质细胞形成修复性牙本质，较强持久的杀菌作用

下表中列出了一些物质的熔点和沸点（1标准大气圧下），根据表中数据回答下列问题：

物质	熔点（℃）	沸点（℃）
水	0	100
萘	80	210
水银	-39	357
酒精	-117	78
氮	-210	-196
氧	-268	-183

（1）表中所列物质在常温下属于固态的是________；氧在-145℃时所处的状态是______

（2）要探究萘的熔化和沸腾过程中温度的变化，应选_______作温度计的测量物质。

（3）如果在1标准大气压下用降温的办法从空气中提取氧和氮，那么温度下降时首先液化被分离出来的是                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  （4）1标准大气圧下，当温度为0℃时，水的状态（  ）

A．一定是固态    　       B．一定是液态    　 

C．一定是固液共存态      　D．以上三种状态都有可能

钢轨闪光焊在高温下通过塑性变形，容易在接合面产生（）形成接头。

前囟的正确测量方法应是：（）

A.对角顶连线

B.对边中点连线

C.邻边中点连线

D.邻角顶连线

E.周径长度

为了切实做到尊重病人自主性或决定。医生向病人提供信息时要避免（）

A.理解

B.诱导

C.适量

D.适度

E.开导