have learned是什么时态

have learned是过去完成时，表示过去某一时间前就已经发生或完成了的动作，对过去的某一点造成的某种影响或是结果，用来指在另一个过去行动之前就已经完成了的事件。

Farmers have learned that they have to migrate if they want to survive.

农民们已经认识到，想要生存就必须外出打工。

Managers have learned to grapple with networking, artificial intelligence, computer-aided engineering and manufacturing.

经理们已经学会了如何应对联网、人工智能、计算机辅助工程和制造。

You are merely reciting facts that you have learned by rote.

你只是在背诵自己死记硬背下来的东西。

In the course of our trip, we have learned a great deal in all the places we visited.

在参观访问过程中，我们随时随地都能学到很多东西。

Learn a little every day and in time you\'ll have learned a lot.

每天学一点儿，日积月累也能学不少。