A.乙醚和石油醚 B.乙醚和乙醇 C.乙醚和環(huán)己烷 D.石油醚和丙酮
A.20%~25% B.26% C.30%~35% D.36%
A.小于3% B.小于1% C.大于3.2% D.大于5.7%