The rules of parallel structure don’t just apply to words and phrases; they also apply to CLAUSES and LISTS AFTER A COLON.
A parallel structure that begins with clauses must keep on with clauses. Changing to another pattern or changing the voice of the verb (from active to passive or vice versa) will break the parallelism.
Example 1
Not Parallel:
The old woman told Hansel and Gretel that they should get a lot of sleep, that they should eat large amounts, and to do some warm-up exercises playing the climb-in-the-oven game.
Parallel:
The old woman told Hansel and Gretel that they should get a lot of sleep, that they should eat large amounts, and that they should do some warm-up exercises before playing the climb-in-the-oven game.
— or —
Parallel:
The old woman told Hansel and Gretel that they should get a lot of sleep, eat large amounts, and do some warm-up exercises before playing the climb-in-the-oven game.
Example 2
Not Parallel:
The pirate expected that he would brandish his cutlass, that there would be time for him to re-adjust his ill-fitting eye patch and that questions would be not be asked by prospective victims. (Note this is also in the passive voice- TERRIBLE! Don’t do that!)
Parallel:
The pirate expected that he would brandish his cutlass, re-adjust his ill-fitting eye patch and take no questions from prospective victims.
Lists After a Colon
Be sure to keep all the elements in a list in the same form.
Example 1
Not Parallel:
The dictionary can be used for these purposes: to bludgeon people who talk loudly in the public library, as a doorstop in drafty houses, to press daisies between sheets of wax paper, and looking up dirty words to see if they have been included.
Parallel:
The dictionary can be used for these purposes: to bludgeon people who talk loudly in the public library; to prop open doors drafty houses; to press daisies between sheets of wax paper; and to look up dirty words to see if they have been included. (Note that not only have I made all the listed clauses parallel, I also changed the punctuation. When a list of clauses follows a colon, it is IMO, better to use semi-colons to separate the clauses rather than mere commas. I think it makes it easier for the reader to see the clauses as clauses meant to be read as units. YMMV).
Chloe Cocking 