build的过去式和过去分词？

双语例句

And if I can build one , well .

如果我可以建立一个，好。

In order to do this you have to build up confidence.

为了做到这一点，你一定要建立起自信。

Or what happens if we have to build that component rather than buy it?

或者“如果我们必须构建而不是买这个部件时会发生什么？”