已知圆C的圆心在直线l₁：x﹣y﹣1=0上，与直线l₂：4x+3y+14=0相切，且截得直线l₃：3x+4y+10=0所得弦长为6，求圆C的方程．

在日本经济产生垄断组织的多种原因中，起主导作用的是（   ）

家庭用煤经过从“煤球”到“蜂窝煤”的变化，其目的是（　　）

阅读下面的对话完成任务。

A: Excuse me, Susan. （1）Is this your backpack?

B: No, it isn't. It's Jack's. （2）My backpack is green.

A: Is your computer game in the lost and found case?

B: No, it's Jack's. And that white eraser is Jack's, too.

A: Do you know Jack?

B: Yes, I do. （3）他是一个英国男孩。He's in Class One, Grade Seven.

A: Oh, what's his telephone number?

B: 100-2116

A: Is Miss Miller his English teacher?

B: Yes, you're right.