Come home before it has gotten dark.

I’d appreciate it if someone would answer my question. Thanks in advance.

What’s the difference between A and B?

A: Come home before it gets dark.

B: Come home before it has gotten dark.

Is B the same as “Come home before it completely gets dark,” or the same as A? Or doesn’t B make any sense?

In the UK, the word ‘gotten’ has not yet taken hold, so we would not use it at all.
I’m not sure whether or not the ‘before it has gotten’ combination works in the US, perhaps someone else can let us know.

[color=blue]“gotten” is the past-participle form of ‘get’ in American English.

“Come home before it has gotten dark.” would be correct, but “Come home before it gets dark.” is the more natural thing to say and I am pretty sure that most native speakers would say it.

Now, my question is different. Long ago I asked this once. Can we call it (whether ‘got’ or ‘gotten’) ‘past participle’? Isn’t it a misnomer?

I would say NO to the first question and YES to the second, for we are not justified in assigning a tense to a ‘tenseless’ verbal form.

A participle can appear in present/past/future tense constructions like:
The PM is given a warm welcome.
The PM was given a warm welcome.
The PM will be given a warm welcome.

Can’t we accept the term Passive Perfective Participle, instead, as it is a participle (non finite form) of the verb ‘give’ and is used in passive constructions (present/past/future) as well as in perfective constructions (present/past/future)?

—Thank you Canadian 45. I think “to have got(ten) dark” means “to get completely dark”, so there’s a slight difference between A and B. However, in both A and B, when someone assumed to come home actually comes home, it has not yet got(ten) dark. So in such a context, there arises no difference, I suppose. What do you think? Sorry I’m late in writing back.

[color=blue]I don’t think there is a darkness difference between the the two sentences.

Thank you Canadian 45.