A.1/2倍; B.1倍; C.1/3倍; D.2倍
A.蓄電池放電; B.發(fā)電機有故障而不放電; C.蓄電池充電; D.發(fā)電機無故障
A.5~10mm B.10~15mm C.15~20mm D.0~25mm