A.2
B.1
C.3
D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]设,则=( )A.2B.1C.3D.-1
[单选题]A.4B.5C.6D.7
[单选题]A.4B.5C.6D.7