1. If $a, b$ are real numbers, satisfying $\frac{1}{a}-\frac{1}{b}=\frac{1}{a+b}$, then the value of $\frac{b}{a}-\frac{a}{b}$ is ( ).
(A) -1
(B) 0
(C) $\frac{1}{2}$
(D) 1
-、1.D.
From the given condition, we know that $b^{2}-a^{2}=a b$. Dividing both sides by $a b$ yields $\frac{b}{a}-\frac{a}{b}=1$.