单项选择题
A.右进左出,前拿后补 B.左进右出,前拿后补 C.右进左出,前补后拿 D.左进右出,前补后拿
A.3/4,48,双层 B.2/3,48,双层 C.3/4,48,单层 D.1/3,24,双层
A.2000mg/L,1斤水,2片 B.2000mg/L,2斤水,1片 C.1000mg/L,1斤水,2片 D.1000mg/L,2斤水,1片