Hello Barbara, The term "gotten" is past tense for the term "to get"- it means to receive something. However, it is not standard English but more of a colloquial slang. I have gotten used to the cold weather or he has gotten us tickets for the concert.

Has gotten -- past Have gotten- present Although gotten is a past of receiving something So the only words you have to pay attention to when speaking about the past and present is "Has" "Have"

"has/have gotten" is the past participle/third form of the verb "to get", used in American English. In British English, it's "have got". "Your English has got much better." (British English) - meaning "Your English has become much better." "Your English has gotten much better." (American English)