1. Calculate
$$
\frac{2010^{2}-2009^{2}}{2010^{2}-2009 \times 2011+2 \times 2009}
$$

The value is ( ).
(A) 1
(B) -1
(C) 2009
(D) 2010
- 1. A.
$$
\begin{array}{l}
\text { Original expression }=\frac{2010^{2}-2009^{2}}{2010^{2}-2009(2011-2)} \\
=\frac{2010^{2}-2009^{2}}{2010^{2}-2009^{2}}=1 .
\end{array}
$$