男,4岁,因发现龋齿就诊。检查发现右下第二乳磨牙近中邻面深龋,腐质未去净,露髓,疼痛。处理方法为
A.冠髓切断B.干髓术C.根管治疗D.直接盖髓E.姑息治疗
参考答案:C
读短文,判断正(√)误(×)。
Man: Can I help you?
Chen Jie: Yes, I want a pair of boots.
Man: What colour do you like?
Chen Jie: I like blue.
Man: What size?
Chen Jie: Size five.
Man: How about this pair?
Chen Jie: They are very nice. How much are they?
Man: They're fifty yuan.
Chen Jie: OK, I'll take them. Here is the money.
Man: Thank you. Bye.
Chen Jie: Bye-bye.
( ) 1. Chen Jie wants a pair of boots.
( ) 2. Chen Jie likes blue.
( ) 3. The boots are 15 yuan.
( ) 4. Chen Jie will not buy the boots.
( ) 5. Chen Jie is on a farm.
(14分)是一种大气污染物,某兴趣小组欲探究的性质及绿色实验的方法,设计如下方案。
(1)装置A中发生反应的化学方程式为 ;
为了实现绿色实验的目标,甲同学重新设计了如下图A′制取装置:
与A装置相比,A′ 装置的优点是:
① ;
② ;
(2)换用A′ 装置后,继续进行下列实验。
I.验证的氧化性:C装置中可选试剂 (填序号);
A.Ba(HCO3)2溶液
B.氢硫酸
C.溴水
D.品红溶液II.验证的还原性:C装置中可用试剂 (填名称);
用该试剂的理由是① ;② ;
(3)D装置中导管下端倒置漏斗的作用是 ;
(4)工业生产硫酸有三个阶段,①其中用黄铁矿制备的化学反应方程式为:___________________________________________________,
②尾气用氨吸收的目的是: 。w^w