Answered By: Chrissine Cairns
Last Updated: Jun 04, 2018     Views: 3

When creating a series or list of items, it is helpful for the reader if the information is parallel, meaning that each item uses the same structure.

This is an example of a series that is not parallel:

On vacation, I swam in the ocean, catching some rays on the beach, and shopped.

In the above example, the verb tenses and forms (swam, catching, shopped) are not the same.

This is an example of that same sentence using a parallel (and clearer) structure:

On vacation, I swam in the ocean, caught some rays on the beach, and shopped.

In the example above, all of the verb tenses and forms (swam, caught, and shopped) are in the past tense

The Purdue Global Writing Center’s Reference Library on the WC homepage contains a tutorial on parallelism.  You may find it very helpful!