
=( ).A.4e
B.4
C.2
D.2e
[单选题]( ).A.2B.4/3C.πD.3
[单选题]( ).A.2B.4/3C.πD.3
[单选题]( ).A.2B.4/3C.πD.3
[单选题]A.B.C.D.E.A、B、C、D都不正确
[单选题]A.B.C.D.E.A、B、C、D都不正确
[单选题]A.3636m/sB.3810m/sC.4000m/sD.3000m/s
[单选题]A.1B.2C.3D.4
[单选题]A.0.30B.0.15C.0.60D.0.90
[单选题]A.49.5,98B.98,49.5C.99,98D.98,99
[单选题]A.49.5,98B.98,49.5C.99,98D.98,99