Amy came back from work, and when she opened the door, the phone immediately started to ring.
"Unpack immediately" is an imperative phrase, specifically a command or instruction telling someone to unpack right away.
Immediately is an adverb.
If the sentence is: I will go to the store immediately...then "immediately" is an adverb. It answers the "when" requirement. "Immediately" is never a preposition.
That sentence is a declarative sentence, a sentence that makes a statement.
"Immediately" is the adverb.
We need to evacuate this building immediately!
Please vacate the premises by 5 PM to allow for cleaning.
Imperative A+
Yes! Immediately exit the building. Immediately turn on your television. Immediately look up Mitch Longley. And so on and so forth.
Both are correct, but they have slightly different meanings. "I have sent it immediately" suggests that the action was completed very recently, while "I sent it immediately" simply states that the action was done promptly. Both are grammatically correct depending on the context of when it happened.
I want you to run to the store immediately and get some ice cream.
If something happens immediately, it happens very quickly, without waiting."Come here, immediately!""He has to be rushed to the hospital immediately.""Immediately after you've finished that book, I want you to help me."