The electric motor is of great importance and value in transportation ,not only because it is used to drive electric cars and electric locomotives ,but also because recently it has come to be used to turn the propellers of ships .

• 电动机在运输上有很重要价值，这不仅是因为用它来驱动电车和电气机车，而且还因为近来已用它来转动轮船的推进器。