对接接头单面焊的方法有哪些？
参考答案：①焊剂铜衬垫法
②水冷滑块式铜衬垫法
③热固化焊剂衬垫法。
以下对各类线缆转弯半径要求描述正确的是（）
A.中继电缆不小于40mm
B.光纤不小于40mm
C.中继线缆不小于35mm
D.网线不小于25mm
I often do my homework on Sundays.
I often watch TV on Saturdays. 
I often read books on Sundays. 
I often play computer games on weekends.