Okay, so I know the textbook rules when to use present perfect and past simple but for some reason I can't decide between these two:
I suddenly realized something.
I've suddenly realized something.
In both cases I mean that my realization happened at this moment. And even though "at this moment" is a time expression so present perfect should not be correct with it, I don't use that in the sentence, and I feel present perfect is usable but I don't know if that's actually correct. I also have a vague memory about reading somewhere that present perfect can be used to emphasize things in certain situations but I may remember wrong, I couldn't find examples of such usage while I was googling for answers.
Also, if this was not "at this moment" but in the past at an unspecified time, would the adverb suddenly indicate a specific time?
Best Answer
To address your second question first, suddenly doesn't indicate a specific time. In this context adding the modifier suddenly makes it sound like you had an epiphany in the sense of definition 2 here. Whatever you realized came into your mind in a split second and instantly changed something for you, such as your perception of or opinions about something. By the time you get around to relating this realization to the people you are with, it's already in the past, even if only a few seconds in the past.
Possible uses:
Here it doesn't make sense to use the present perfect because the event is well in the past, so I use the simple past tense. (Apologies that my example prose does not compare to great literature. Please don't worry if you think they have unrelated grammar mistakes.)
In this example Jane is relating something she realized while Sandy was speaking. The present perfect is used because she is relating "a past event that has present consequences," to quote Wikipedia.