—What a lovely card! Where did you buy it?—I made it by _______.
A:me
B:I
C:mine
D:myself
温度/℃
20
30
50
60
80
溶解度
(g/100g水)
K2CO3
110
114
121
126
139
KNO3
31.6
45.8
85.5
169