答案：A
設 $f(x) = x^{2009} + x^{2008} + \cdots + x$。由此，所求的餘數
設 $f(x) = x^{2009} + x^{2008} + \cdots + x$。由此，所求的餘數
$\begin{array}{cl}
= & f(-1) \\
= & (-1)^{2009} + (-1)^{2008} + \cdots + (-1) \\
= & 1005(-1) + 1004 (1) \\
= & -1
\end{array}$
