A.1
B.2
C.3
D.0
[单选题]A.1B.2C.3D.0
[单选题]A.0B.1C.2D.
[单选题]A.a>1B.a>0C.a为任意实数D.a<1
[单选题]A.B.0C.D.
[单选题]A.4πB.3/4πC.2πD.4π/3
[单选题]A.B.C.D.
[单选题]A.-2xdxB.C.D.