Question

which sentence or sentences have correct parallel structure?
getting from my english class to my science lab requires me to go down the stairs, run across the quad, into the science building, and down the corridor to the lab—all in three minutes!
getting from my english class to my science lab requires me to go down the stairs, across the quad, into the science building, and down the corridor to the lab—all in three minutes!

Explanation:

Parallel structure requires consistent grammatical form for listed items. The first sentence mixes a verb phrase ("run across the quad") with prepositional phrases, breaking consistency. The second sentence uses only prepositional phrases (all starting with prepositions: down, across, into, down) for the sequence of actions, maintaining parallelism.

Answer:

Getting from my English class to my science lab requires me to go down the stairs, across the quad, into the science building, and down the corridor to the lab—all in three minutes!