Russia

1. Yes. It's possible you may go again.

2. No. I was in Russia when... or I visited Russia when... or I went to Russia when...

Generally, don't use present perfect when you refer to a specific time.

Thanks Grammar Geek
Very soon Mr Vladimir Putin will leave office.
When he is out of office, I am free to say the following.
2] I visited Russia when Mr Vladimir Putin was at the helm.

3] I visited Russia when Mr Vladimir Putin was at the helm and I wish I visited Russia when Mr Vladimir Lenin was at the helm.
I was not in this world when Mr Vladimir Lenin reigned ov

I visited Russia when Mr Vladimir Putin was at the helm and I wish I had visited Russia when Mr Vladimir Lenin was at the helm.

As a style issue, I wouldn't use an idiom like "at the helm" twice in the same sentence. Use something like "in charge" or "ran things" for the second use.

Thanks Grammar Geek
I wish I had visited Russia ...
I just want to know whether the above is subjunctive.
It may be hypothetical.
Please tell me.

Yes, in "I wish I had visited Russia", "had visited" is used to show it's hypothetical. You didn't visit it.
And the reason why you can say "I've been to Russia" is that you are just talking about your experience. You have been to a lot of countries (in your life, so far), and you have visited Russia (in your life, so far). But when you are thinking of a specific occasion in the past, you use

Do you know his telephone number?
Instead of saying 'I am sorry I don't know' we could say ' I wish I knew'.
I just want to know the sentence 'I wish I knew' is subjunctive.
Please tell me.
It can't be hypothetical.
I don't have license to drive lorries and buses. So I can say the following.
I wish I could drive buses and lorries.

Hi,
I call it subjunctive, which is pretty much what I call everything that seems to be a past tense but doesn't refer to the past.
I wish I knew his number (...but I don't know).
I wish I could drive (...but I can't).
That's why I said there's something hypothetical in those constructions.

0I am surprised to learn that it is subjunctive. Because the subjunctive has the smack of conditionality. I don't find that nature in 02br
00those sentences. 0-