当前学科:船舶动力装置
  • 题目: 单选
    The successful operation of any engine or machine and () depend on effective lubrication.

      A . their no trouble period
      B . their freely trouble period
      C . its free trouble life
      D . its trouble-free life

    答案: <查看本题扣1积分>

    查看答案

    答案不对?请尝试站内搜索