A:that; which
B:where; that
C:in which; what
D:where; which
a÷b=c(a,b都大于0),当b<1时,( )
已知f(x)为偶函数,当x≥0时,f(x)=﹣(x﹣1)2+1,则满足ff(a)+12=12的实数a的个数为( )
下列四台显微镜的目镜和物镜的放大倍数,在观察植物根尖细胞时,视野中细胞放大倍数最大的显微镜是( )