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。