If the items are not the same part of speech and the same form, change the items so that they are.
|Revision:|| ||must commit a significant amount of time to daily care|
| ||and||must know how to identify signs of illness or injury in the horse|
Note that words that appear in the beginning of all of the series items can sometimes be deleted after the first occurrence. In this case, must does not have to appear twice. We can instead reanalyze the list as consisting of two verbs that follow must: commit and know. Both verbs are now in the infinitive form.
Revision: To keep horses at home, the owner must commit a significant amount of time to daily care and know how to identify signs of illness or injury in the horse.
Sometimes more complex lists require another approach. Consider the following sentence:
Example: The horses need to be groomed, watered, fed, and clean their stalls.
Isolating the items in the series results in this list:
| ||groomed |
|and||clean their stalls|
The first three items are all past participle forms referring to actions that must be performed on the horses. The fourth is an uninflected form referring to an action that must be performed on the stalls. Therefore, we cannot simply change the fourth form to the past participle cleaned and stop there. The best way to fix this sentence is to revise it so that it contains two clauses:
Revision: The horses need to be groomed, watered, and fed, and their stalls need to be cleaned.
Now we have a series of two parallel clauses. Within the first clause, we also have a series of three parallel items. The following list format may help you to see these features.
|The horses need to be|| |
|and||their stalls need to be cleaned|