单项选择题
A.2.0;60 B.1.5;40 C.1.5;60 D.2.0;40
A.降低;3/8~1/2 B.降低;1/2~1 C.升高;3/8~1/2 D.升高;1/2~1
A.25 B.35 C.37 D.27