Catching an Accidental Shift

“She walks into the room and grabbed her coat.” Read that sentence quickly and it might slide right past you — but something in it doesn't match. It starts in present tense (“walks”) and switches to past tense (“grabbed”) partway through, without any reason for the change. This kind of accidental shift, in tense and sometimes in mood, is remarkably easy to write and surprisingly hard to catch, because once you already know what a sentence is trying to say, your eyes tend to skim past its grammar rather than check it.

Why does a mistake this obvious slip past a careful writer so often? Mostly because writing happens fast, and a writer's attention is on the idea, not the tense of every individual verb. The shift stays invisible on a silent read-through precisely because silent reading relies on the same skimming habit that let the sentence get written wrong in the first place.

A test that actually catches it

Reading a paragraph out loud breaks that habit, because your ear notices a mismatch your eyes were gliding right past. This is worth doing especially at the start and end of a scene — two spots where writers often drift into present tense to build immediacy, then forget to hold it for the whole passage.

Not every shift is a mistake, though. A story can deliberately change tense between sections, and that's a choice, not an error. The only real problem is the accidental kind: a single sentence that changes tense in the middle of describing one continuous moment, for no reason a reader could ever point to. That's the shift worth reading aloud to catch, every time.