comma splice and placement of full stop

Could somebody please help? Thanks.

I can't say that this is required, but I would put a semicolon after wish, and a comma after hence. I believe that it is correct that the full stop is within the inverted comma in British usage. Therefore, I would write: The verb should be in the past tense as this is a wish; hence, the sentence should read 'I wish I knew what was happening.'

I would use the semicolon because the initial clause is independent, but the following clause is dependent.

Great answer! I would use the semicolon, too, because it is an adverb and not a conjunction.

Thanks, Setanta, for the great answer.