设 $\alpha, \beta$ 是两个平面, $m, l$ 是两条直线, 则下列命题为真命题的是
$\text{A.}$ 若 $\alpha \perp \beta, m / / \alpha, l / / \beta$, 则 $m \perp l$
$\text{B.}$ 若 $m \subset \alpha, l \subset \beta, m / / l$, 则 $\alpha / / \beta$
$\text{C.}$ 若 $\alpha \cap \beta=m, l / / \alpha, l / / \beta$, 则 $m / / l$
$\text{D.}$ 若 $m \perp \alpha, l \perp \beta, m / / l$, 则 $\alpha \perp \beta$