fronted prepositional phrase

A2 point 1 and the only point in the category of FOCUS / FRONTING is defined as: ‘a prepositional phrases in the front position for focus.’
“At the time, I had a girlfriend, so I didn’t talk to her.” This is an example of putting a prepositional phrase at the start of a sentence which is what pre-intermediate students can do.

fronted prepositional phrase