Set up a list so that each chunk of the list appears in the same grammatical form.
(1) What does NON-PARALLEL CONSTRUCTION look like?
When I have free time, I enjoy watching movies, to go for a walk, and call my friend back home. [Three verbs appear in three different forms.]
(2) Why is NON-PARALLEL CONSTRUCTION problematic?
In addition to sounding awkward, non-parallel construction can cause confusion if the applicability of an initial word or phrase to multiple elements in a list is not clear.
(3) How to fix NON-PARALLEL CONSTRUCTION?
When I have free time, I enjoy watching movies, going for a walk, and calling my friend back home. [All three verbs appear in same form.]