1. 以…换取
    If you trade off one thing against another, you exchange all or part of one thing for another, as part of a negotiation or compromise.

    e.g. They cynically tried to trade off a reduction in the slaughter of dolphins against a resumption of commercial whaling...
           他们见利忘义地试图以减少屠杀海豚数量作为交换条件，重启商业捕鲸。
    e.g. There is a possibility of being able to trade off information for a reduced sentence.
           有可能以情报换取减刑。

2. (为达到利己目的)利用
    If someone trades off something, they make use of it for their own advantage, often in an unfair way.

    e.g. They would be able to trade off their looks and manage on that alone.
           他们将能利用自己的外表，并且单靠这一点就可以。