观测线在基牙的近缺隙侧距面远,远缺隙侧距离面近的是哪类观测线()。
A.Ⅰ型观测线
B.Ⅱ型观测线
C.Ⅲ型观测线
D.Ⅳ型观测线
E.Ⅴ型观测线
参考答案:A
用NA表示阿伏加德罗常数的值。下列叙述正确的是
A.常温下,18g H2O中含H2数目为NA
B.标准状况下,22. 4LH2O中含有化学键的数目为2NA
C.将0.5mol SO2通入足量水中,充分反应后可得到H2 SO3分子数为0.5NA
D.常温常压下,Na2O2与足量H2O反应,共生成0.2mol O2,转移电子的数目为0.4 NA
Mr. Wang is very strict _______ his son. And he is very strict _______ everything he does. [ ]
A. with, with
B. with, in
C. in, in
D. in, with