A:CaSiO4
B:Ca2SiO3
C:CaSi2O3
D:CaSiO3
— Were there any cows?
— ________.
If I _______ Tom, I _______ the police for help.
下列所使用的试剂必需现配现用的是①斐林试剂 ②二苯胺试剂 ③双缩脲试剂 ④龙胆紫