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