Better sentence-writing in 30 minutes a day - Dianna Campbell 1995

A Final note
Complex sentences
Sentence combining: basic strategies and common problems

You may have noticed that some of the subordinating conjunctions were listed earlier as prepositions. Don’t let this confuse you. Some words can be used as both subordinating conjunctions and prepositions, depending on how they are used.

1. (a) Wendy went to the Halloween party after school.

(b) She had to go back for her broom after she left the party.

2. (a) I’d like to see you before the spring break starts on Monday.

(b) I’d like to see you before the spring break.

3. (a) Daniel wasn’t completely at home in Detroit until his third year there.

(b) Until Daniel had been in Detroit for three years, he wasn’t completely at home in the city.