2. If $\alpha, \beta \in \mathbf{R}$, then $\alpha+\beta=90^{\circ}$ is a ( ) condition for $\sin \alpha+\sin \beta>1$.
(A) Sufficient but not necessary
(B) Necessary but not sufficient
(C) Sufficient and necessary
(D) Neither sufficient nor necessary
2. D.

When $\alpha=0, \beta=90^{\circ}$, $\sin \alpha+\sin \beta=1$.
When $\alpha=\beta=60^{\circ}$,
$\sin \alpha+\sin \beta=\sqrt{3}>1$, but $\alpha+\beta \neq 90^{\circ}$.