A:①②
B:①③
C:②④
D:③④
_____a dog. We don't know_____ name.
3.2÷0.8=
7.2÷0.9=
3.2+5.8﹣0.7=
0×1.25×8=
910÷70=
36×25%=
0.5×0.5÷0.5=
1.03﹣0.44=
设函数f(x)=sin(2x﹣π2)(x∈R),则f(x)是( )
下列说法正确的是( )①教科书是长方形;②教科书是长方体,也是棱柱;③教科书的封面是长方形.