Are the verb tenses in the sentence consistent, or do they shift unnecessarily?
the squirrel stuffed the pecan into its mouth and scampered up the tree.
a. the verb tenses shift.
b. the verb tenses are consistent.

B. The verb tenses are consistent.

The verbs are stuffed and scampered. Both are in the past tense form.

Verb tense consistency refers to keeping the same tense throughout a clause. If you have two or more tenses, start a new clause or a new sentence.

Verb tense consistence is very important because the sentence as a whole must impart only a complete thought. If the tenses are not consistent, the reader may become confused upon reading the sentence and may not understand the thought the sentence need to deliver.