I am learning syntactic theory from the book "English Syntax and Argumentation." I got decent understanding of S, NP, VP, I. I do not use DP or TP because the textbook does not use it. However, I have problem understanding constituency for sentences where the sentence starts with an adjunct or the adjunct is at sentence level. Here are three examples:
By next October he will have been serving as town clerk for thirty-two years.
After all those years, he finally married the girl of his dreams.
Frankly, this whole paragraph needs work.
I have problem with the parts in bold. Should they be considered as Adjuncts to the Verb Phrase or the sentence? If they are part of the Verb Phrase, how do I justify having them at the beginning of the sentence.
In the third one, "Frankly" applies to the whole sentence. I've seen it being called sentence level adjunct or disjunct. I haven't seen any three that has a part for a sentence level adjunct.
Based on @user6726 comment, I rephrased the question to be about constituency and not about drawing tree diagrams. Hope this clarifies the question.