—He may live No.l6, Horse Bridge Road, Ken Town.

Boys and girls,

Attention, please! Do you know 1to keep safe in our daily（日常的）life? Today I’d like2 you some ways to keep safe.

1  Always play in a 3 place. A park is a safe place4 there are no cars or buses in it.

2  5 the traffic rules, please! Before crossing a road,6 and look both ways ——look left, look right and look left 7.

3  Never put your head or hands 8 a car, a bus or a train. Many people get 9 or lose their lives by doing so.

4  Don’t 10 a stranger（陌生人）or go with him/her.

That’s all. All the students should obey the rules anytime(任何时候).

如图，一宽为2cm的刻度尺在圆上移动，当刻度尺的一边与圆相切时，另一边与圆两个交点处的读数恰好为“1”和“4”（单位：cm），则该圆的半径为（　　）