已知 $l \perp$ 平面 $\alpha$, 直线 $m \subset$ 平面 $\beta$. 有下面四个命题:
(1) $\alpha / / \beta \Rightarrow l \perp m$;
(2) $\alpha \perp \beta \Rightarrow l / / m$;
(3) $l / m \Rightarrow \alpha \perp \beta ;$
(4) $l \perp m \Rightarrow \alpha / / \beta$.
其中正确的两个命题是( )
$\because l \perp \alpha, \alpha / / \beta, \therefore l \perp \beta, \because m \subset \beta, \therefore l \perp m$, 故(1)正确; $\because l / / m, l \perp \alpha, \therefore m \perp \alpha$, 又 $\because m \subset \beta, \therefore \alpha \perp \beta$,故(3)正确.