一期分炉煤皮带称重系统零点校验最大允许误差是多少？
参考答案：
最大允许误差是小于50千克。
—Have you been teaching here since graduation?
—No, I _____ on a farm for five years．
A．had worked
B．have worked
C．was working
D．worked
简述带肋钢筋的尺寸测量方法。
