2006-II-13
答案:D
$\begin{array}{ccccccccccc}
x & : & y
… Read $\begin{array}{ccccccccccc}
x & : & y
$\begin{array}{cl}
& 1:8~000 \\
$\begin{array}{cl}
= &
$\begin{array}{cl}
= & 1 : 5~000 \
$\begin{array}{cl}
= &
$\begin{array}{cl}
= & 3 \times
$\begin{array}{cl}
= & 36\text{
$\begin{array}{rcl}
\
$\begin{array}{cl}
= & 1 : 20\ 000