电动系仪表的准确度比电磁系仪表高。( )
参考答案：对
He was about to do his homework when an unusual noise ________ his attention.
A．arrested
B．affected
C．attacked
D．attended
电缆在电杆两侧的第一只挂钩各距电杆（）mm，允许偏差±20mm。
A、200
B、250
C、300
D、400
