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。