如图，CD是经过∠BCA顶点C的一条直线，且直线CD经过∠BCA的内部，点E，F在射线CD上，已知CA=CB且∠BEC=∠CFA=∠α．
（1）如图1，若∠BCA=90°，∠α=90°，问EF=BE-AF，成立吗？说明理由．
（2）如图2，若0°＜∠BCA＜90°，请你添加一个关于∠α与∠BCA关系的条件，使结论EF=BE-AF仍然成立．你添加的条件是，并给出证明．
（3）如图3，若直线CD经过∠BCA的外部，∠α=∠BCA，请提出EF，BE，AF三条线段数量关系的合理猜想，并给出证明．

—How amazing the Great Wall is!—Yes, but it is very ____ to climb it.(tire)

“We must keep ____ in the library,”the librarian said to me____. (quiet)

—The accident was really terrible,wasn’t it?—Yes,it was.The young man on the bicycle was too ____.(care)

老师有重要的事情要告诉我们。The teacher has ____ to tell us.

—Do you want to play football with me?—That sounds     . I like playing foofball.

I’m very busy at the moment. So if you don’t have      to say, please just leave me alone.

The students from Xinjiang enjoy staying in our school because everyone is        to them.

He is       and he has an     sister.

—What          news it was!—Yes, all of the children were very            .