I'm not going to let them get one over on me!
我决不让他们胜过我！
Now let me see ─ how old is she now?
让我想一想，她现在多大了呢？
Let's take the problems in a different order.
咱们换一个顺序来处理这些问题吧。
Let's be practical and work out the cost first.
咱们实际一点儿，先计算一下成本费用。
Let's attack one problem at a time.
咱们一次全力处理一个问题。
It is important not to let things get out of perspective.
重要的是不要把事情轻重倒置。