Answer:
The dependent clauses would be the following ones:
- While Patrick set the table
- If he is running late
- Before she boarded the plane
Step-by-step explanation:
A dependent clause is a group of words with a subject and a verb. It does not express a complete thought so it is not a sentence and can't stand alone. It depends on the the main clause to complete its meaning. These clauses include adverb clauses, adjective clauses, and noun clauses. In the choices presented, all the dependent clauses are adverb clauses.
Adverbs clauses modifiy verbs and begin with a subordinating conjunction (while, if, before). The fact that the following clauses are grammatically incorrect proves that they can stand alone as sentences (1, 2, 3).
1. *While Patrick set the table
2. * If he is running late
3. * Before she boarded the plane