Which is the present-progressive form of verb caminar?

The present progressive form of the verb "caminar" (to walk) is caminando.

Here's how it's formed:

* Present participle: "caminando" (formed by adding "-ando" to the stem "camin")

* Auxiliary verb "estar": This verb indicates ongoing action.

So, the full phrase would be something like: "Estoy caminando" (I am walking).