* Present Progressive: *I am eating*
* Past Progressive: *I was eating*
* Future Progressive: *I will be eating*
* Present Perfect Progressive: *I have been eating*
Why it's not twelve:
Some resources might list twelve because they include:
* Perfect Progressive tenses in all three time periods: (e.g. *I had been eating*, *I will have been eating*)
* Variations for active and passive voices: (e.g., *The ball is being thrown* - passive present progressive)
However, these are not typically considered separate forms, but rather variations within the four core progressive forms.
In summary: While there are various ways to categorize verb tenses, the core progressive forms in English are four: present, past, future, and present perfect progressive.