下列疾病中,不属于遗传病的是( )
A:先天性聋哑
B:色盲
C:艾滋病
D:血友病
-- Wait a minute. Don’t cross the street _______ the traffic lights turn green.
— Would you like to tell me something about Jiangsu?
— All right. Jiangsu is _________ thirteen big cities.
如图,点A、B是反比例函数 y=3x (x>0)图象上的两个点,在△AOB中,OA=OB,BD垂直于x轴,垂足为D,且AB=2BD,则△AOB的面积为____
绘制某所中学的平面地图,其图幅大小与所选用的比例尺是相对应的,规律是( )