已知,直线AB∥CD (1)如图1,点E在直线BD的左侧,猜想∠ABE、∠CDE、∠BED的数量关系,并证明你的结论; (2)如图2,点E在直线BD的左侧,BF、DF分别平分∠ABE、∠CDE,猜想∠BFD和∠BED的数量关系,并证明你的结论; (3)如图3,点E在直线BD的右侧,BF、DF分别平分∠ABE、∠CDE;那么第(2)题中∠BFD和∠BED的数量关系的猜想是否仍成立?如果成立,请证明;如果不成立,请写出你的猜想,并证明. It ________ nearly two weeks ______ I had received his letter. A. is, that B. was, that C. is since D. was, since