A.2.10~2.30
B.1.75~1.95
C.1.45~1.65
D.1.15~1.35
[单选题]A.2.10~2.30B.1.75~1.95C.1.45~1.65D.1.15~1.35
[单选题]A.2.10~2.30B.1.75~1.95C.1.45~1.65D.1.15~1.35
[单选题]A.α=45°B.α=60°C.D.
[单选题]A.α=45°B.α=60°C.D.
[单选题]A.DN150B.DN200C.DN250D.DN300
[单选题]A.DN150B.DN200C.DN250D.DN300
[单选题]A.与a无关随λ得增大而增大B.与a无关随λ的增大而减小C.与λ无关随a的增大而增大D.与a无关随λ的减小而减小
[单选题]A.条件(1)充分,但条件(2)不充分。B.条件(2)充分,但条件(1)不充分。C.条件(1)和条件(2)单独都不充分,但条件(1)和条件(2)联合起