7. Let $\alpha , \beta$ be two planes. Then $\alpha / / \beta$ is a necessary and sufficient condition for\\
A. $\alpha$ contains infinitely many lines parallel to $\beta$\\
B. $\alpha$ contains two intersecting lines parallel to $\beta$\\
C. $\alpha , \beta$ are both parallel to the same line\\
D. $\alpha , \beta$ are both perpendicular to the same plane