单项选择题
A.淀粉B.葡萄糖C.果糖D.蔗糖
A.10g/L~15g/LB.20g/L~30g/LC.35g/L~45g/LD.60g/L~70g/L
A.介体传播B.非介体传播C.外力传播D.自然传播