题目

---- Shall I give you a ride as you live so far away?   ----- Thank you. ___________.    A. It couldn’t be better.   B. Of course you can   C. If you like   D. It’s up to you. 答案：A图中为梯形纸片ABCD，E点在BC上，且∠AEC= ∠C= ∠D= 90°，AD=3，BC= 9，CD=8. 若以AE为折线，将C折至BE上，使得CD与AB交于F点.则BF长度为 [     ]A. 4. 5     B. 5  C. 5. 5     D. 6