1. Economy is one powerful motive for campinge after the initial outlay upon the equipment.
    在开初支付了装备的费用后, 想省钱是露营的一个主要动机。

2. Economy is one powerful motive for camping,
    图省钱是露营的一个主要动机，

3. It is probably a mistake to credit dolphins with any motive of lifesaving.
    认为它们有救人的动机可能是错误的。

4. The police could not find a motive for the murder.
    警方未能找出谋杀者的动机.

5. There was no ulterior motive in his proposal.
    他的建议里没有不可告人的动机。

6. It may be a mistake to credit dolphins with any motive of life-saving.
    相信它们具有救生的动机可能是错误的.