Could someone explain the difference between a phrase ( doesn't contain a verb and subject?) and a clause ( contains a tensed verb and a subject?).

When do phrases end and begin? I can't for the life of me figure this out.

Example: the sentence contains marking for Prepositional phrase=PP, RRC= restrive relative clause, & an Appostive


Hillary Clinton went through 15 years [of this stuff]-PP [before becoming, [under Obama]-PP, [the woman everyone loves]-Appositive, a woman [whom Chris Cillizza just dubbed "the new Teflon Clinton."]-RRC]-PP


I don't understand why before becoming is a large prepositional phrase compared to the other markings.
I took out the markings to show that the entire sentence is marked as a prepositional phrase.

[before becoming, under Obama, the woman everyone loves, a woman whom Chris Cillizza just dubbed "the new Teflon Clinton."]-PP

'becoming' is not a complete verb.

It can only be used as such in conjunction with an auxiliary verb such as was becoming, is becoming etc.

 

Strictly it is the gerund part of the verb which is the posh name for a verb used as a noun.

 

'before' is a preposition

 

So you have preposition + noun = preposition phrase