describe的现在分词形式是什么

例句：

Describe how you did it.

谈谈你是怎样做这事的`。

I cannot describe it, I can't find the words

我描述不上来，我找不到合适的字眼。

We asked her to describe what kind of things she did in her spare time

我们请她描述一下她业余时间都在做什么。

The effect is almost impossible to describe

这种影响几乎无法用言语描述。