Identify the sentence that incorporates parallel structure.

a. My week at camp included rock-climbing, mountain biking and sleep.

b. During my week at camp, I swam, hiked, biked and skiing on the lake.

c. My week at camp consisted of playing soccer, riding mountain bikes and crafts.

d. During my week at camp, I scaled the climbing wall, built a fort, and jumped on the trampoline.

d. During my week at camp, I scaled the climbing wall, built a fort, and jumped on the trampoline.

Parallelism happens when there is a similar grammatical structure within a sentence or across a group of sentences so that there is a similar sound, meaning, or meter. It is important to use parallelism when listing actions. In sentence D, all of the activities in the list have the same structure. They all begin with a past tense verb (scaled, built, jumped) and end in a noun (wall, fort, trampoline). A is wrong because the first two verbs in the list end in - ing, but sleep does not. I should be: rock-climbing, mountain biking and sleeping. In B the first three verbs are all past tense, but skiing is not. It should be: swam, hiked, biked, skied. C is wrong because the structure is a verb ending with - ing followed by a noun. There is no verb before crafts in the list. It should be: playing soccer, riding mountain bikes, and making crafts.