（2013•浙江）直线y=2x+3被圆x²+y²﹣6x﹣8y=0所截得的弦长等于　_________　．

短文填空。(根据首字母提示填空)

A: Shall we have dinner now?

B: I can't eat a  1   I'm not feeling well today.  I have a headache.

A: You may b  2   ill.You must s  3   the doctor i  4   you are ill.

B: I don't know w  5   the doctors are.

A: I know agood d  6   near the park. Shall I call him?

B: No, thanks. I t  7   feel better tomorrow.

A: Well, go to bed early and have enough r  8  .

B: I have to study. We are going to have an English test tomorrow. I'm a  9   I'll fail(不及格)in the test.

A: B  10   I'm afraid you can't study with a terrible headache.