A:质子数和中子数
B:质子数和电子数
C:中子数和电子数
D:核电荷数和电子数
—One. They two in the future, I guess.
①加入氯水 ②加入KMnO4溶液 ③加入NH4SCN溶液.
水稻育秧期间,如长期水淹,会导致烂种烂秧,其原因是
— Just by hands, I didn't use any ____ (tools/science).