1. Calculate $\frac{2009^{2}-2008^{2}}{19492009^{2}-19492008 \times 19492010+2 \times 2008}$ $=(\quad)$.
(A) 1
(B) -1
(C) 2008
(D) 2009
-1.А.
Let $19492009=a, 2008=b$. Then
$$
\begin{array}{l}
\text { Original expression }=\frac{(b+1)^{2}-b^{2}}{a^{2}-(a-1)(a+1)+2 b} \\
=\frac{b^{2}+2 b+1-b^{2}}{a^{2}-a^{2}+1+2 b}=\frac{2 b+1}{2 b+1}=1 .
\end{array}
$$