一句英文歌詞問題。?

let, let, letting
eg:-
She lets it go.
She really lets it go.
They let it go.
Let  go of it to stop the letting.
She's not letting it go-不允許,不讓------(grammar)2 forms of a verb (past participle and present participle)which may be used in compound forms of the verb (Ving) or as adjective.
Thanks for the compliment of praise, Helen.