All right, this is a quickie lesson for writers who've barreled past the usual subject-verb agreement problems. For the sake of refresher, I'm writing in present tense:
The books[plural] stacked against the wall topple[also plural] down the stairs in the wake of his sudden descent.
So, subject and verb [plural subject] agree [thus plural verb] in number.
Let's take it one step further. Subject and verb must also agree in sense. Consider this sentence, most recently brought to my attention during a critique group session by my fellow writers, much to my chagrin.
A shadow of dread sliced through his gut.
Think about shadows. Do they slice? Not exactly. They're sometimes sharp enough to slice, but often they're more insubstantial, smoky, swirly, ephemeral, losing and gaining shape. Subject-verb agreement here would have me pick a verb that agrees in sense with the subject.
So I did. The sentence now reads:
A shadow of dread whorled through his gut like smoke.
I took some liberties with the verb, it's true. But here, the subject and verb agree in sense. The subject begins a certain image and the verb strengthens and plays on that image to deepen the feeling.
Let's see your own examples! Lines you've massaged for more depth and clarity via SV agreement.