题干
— I regret to say that I have shouted at you the other day．
— Forget it． I was a bit out of control myself．
— Forget it． I was a bit out of control myself．
A：shouldn’t
B：mustn’t
C：couldn’t
D：mightn’t
答案(点此获取答案解析）
A
的圆O位于y轴左侧，且与直线x+2y=0相切，则圆O的方程是