如图.
(1)如果∠1=∠B,那么________∥________,根据是________________;
(2)如果∠3=∠D,那么________∥________,根据是________________;
(3)如果要使BE∥DF,必须∠1=________,根据是________________,
如图.
(1)如果∠1=∠B,那么________∥________,根据是________________;
(2)如果∠3=∠D,那么________∥________,根据是________________;
(3)如果要使BE∥DF,必须∠1=________,根据是________________,