Identify the prepositional phrases in the sentence: 'Timmy sat behind the table, waiting to surprise his sister who walked through the door'.

• A. To surprise his sister
• B. Behind the table and through the door
• C. Timmy sat behind
• D. The door

Answer: (B)

Prepositional phrases are units that start with a preposition and include its object, often telling where, when, or how something happens. In this sentence, the prepositions are behind and through. Behind the table describes where Timmy sat, and through the door describes where his sister walked. The phrase to surprise his sister is an infinitive phrase (to + verb), not a prepositional phrase, and the door by itself is just a noun phrase, not a prepositional phrase. So the two prepositional phrases present are behind the table and through the door.