单项选择题
A.5~10B.10~15C.15-25D.3~5
A.100%乙腈B.100%甲醇C.90%乙腈D.90%甲醇
A.10-2~10-3TorrB.10-3~10-4TorrC.10-2~10-4TorrD.10-5~10-6Torr