A. 4 B. 5 C. 6 D. 8
A. low water in the expansion tank B. improperly seated valves C. low fuel oil pressure D. worn or broken cylinder liner sealing ring
A. 准运证和购销合同原件 B. 发票 C. 准运证复印件 D. 购销合同复印件
A. 正确 B. 错误