过点（1，2）与圆x²+y²=1相切的直线方程是[ ]

A．x=1

B．3x﹣4y+5=0

C．3x﹣4y+5=0或x=1

D．5x﹣4y+3=0或x=1

填空。  

1．关羽失荆州  ——                                   

2．                                             ，春江水暖鸭先知。  

3．春雾                 ，夏雾                 ，秋雾                 ，  冬雾                        。  

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