<image>As shown in the , in the tetrahedron $$ABCD$$, $$CB=CD$$, $$AD\perp BD$$, points $$E$$ and $$F$$ are respectively the midpoints of $$AB$$ and $$BD$$. Prove that: 
$$(1)$$ The line $$EF$$ is parallel to plane $$ACD$$; 
$$(2)$$ The plane $$EFC$$ is perpendicular to plane $$BCD$$.