
A.(x-2y)y′=2x-y
B.(x-2y)y′=2x
C.xy′=2x-y
D.-2yy′=2x-y
[单选题]A.(x-2y)y′=2x-yB.(x-2y)y′=2xC.xy′=2x-yD.-2yy′=2x-y
[单选题]A.<10μmB.10~60μmC.70~100μmD.200~300μmE.>300μm
[单选题]A.B.C.D.膜上载体和通道蛋白的共同作用E.
[单选题]A.m=4,n=3B.m=3,n=4C.m=-9,n=-4D.m=9,n=6E.m=5,n=3
[单选题]A.m=4,n=3B.m=3,n=4C.m=-9,n=-4D.m=9,n=6E.m=5,n=3
[单选题]A.0.4B.0.6C.0.5D.0.3
[单选题]A.0.4B.0.6C.0.5D.0.3
[单选题]A.B.下颌前突C.D.牙间隙E.