points on verb tense shift

Candy, 

A verb tense shift is when a writer changes the tense of their verbs while writing on the same topic.  Generally the change is from present to past tense and often confuses readers.  

Verb tense shifts happen very often when people try to write about literature, film, or other stories.  A good thing to keep in mind is that whenever we want to discuss stories, we always do so in the present tense, regardless of when the piece was produced.

I hope this helps.

Kim J.