(1) ammonia is liquid, phosphate rock powder is gray solid, potassium chloride and ammonium sulfate are white solid, so A is ammonia water and B is phosphate rock powder; C and D are one of potassium chloride and ammonium sulfate;

(2) adding water to dissolve, wherein potassium chloride and ammonium sulfate are dissolved in water, and phosphate rock powder is insoluble in water;

(3) Add slaked lime for grinding, and the pungent smell is ammonium sulfate, so D is ammonium sulfate and C is potassium chloride.

So the answer is: ammonia; Phosphate rock powder; Potassium chloride; Ammonium sulfate