1. The number of positive integer solutions to the indeterminate equation $2(x+y)=x y+7$ is ( ).
(A) 1
(B) 2
(C) 3
(D) 4
-、1.B.
Assume $x \geqslant y$. From the condition, we have $(x-2)(y-2)=-3$. Then $\left\{\begin{array}{l}x-2=3, \\ y-2=-1\end{array}\right.$ or $\left\{\begin{array}{l}x-2=1, \\ y-2=-3 .\end{array}\right.$
Solving these, we get $x=5, y=1$ or $x=3, y=-1$ (discard).
Therefore, the original indeterminate equation has two sets of positive integer solutions: $(5,1),(1,5)$.