我们规定这样一种运算:如果ab=N(a>0,N>0),那么b就叫做以a为底的N的对数,记作b=logaN。例如,因为23=8,所以log28=3,那么log381=( )。
4
Though_____ money, his parents managed to send him to university. [ ]
A. lacked
B. lacking
C. lacking of
D. lacked in
已知抛物线顶点坐标为(2,1),且当x=0时,y=-3,则抛物线的解析式为______.