A:不变
B:扩大为原来的2倍
C:缩小为原来的12
D:扩大为原来的4倍
右图实线是函数y=f(x)(0≤x≤2a)的图象,它关于点A(a,a)对称.如果它是一条总体密度曲线,则正数a的值为( )
You ______ go and see a doctor at once because you're got a fever.