It's a common little hiccup, isn't it? You're writing along, feeling pretty good about your sentence, and then you hit it: 'vary' or 'varies'? Which one is it? It's like trying to decide if you need an 's' on the end of a verb when talking about something happening right now. Let's break it down, nice and easy.
At its heart, 'vary' is a verb that means to be different, to change, or to make something different. Think of it as the root, the core idea of change or difference. When we talk about things that are inherently different from one another, or when something is in the process of changing, 'vary' is the word we're dancing with.
Now, 'varies' is simply the third-person singular present tense form of 'vary'. What does that mean in plain English? It means when your subject is a single person, place, or thing (he, she, it, the dog, the weather, the price), and you're talking about what it's doing now, you add that 's'.
So, if you're observing that test scores aren't the same everywhere, you'd say, "Test scores vary from school to school." Here, 'test scores' is plural, so we use the base form of the verb. But if you're talking about a single aspect, like the difficulty of those tests, you might say, "The difficulty of the test varies depending on the subject." See the difference? 'Difficulty' is singular, so it gets the 's'.
It's not just about static differences, either. 'Vary' also captures the dynamic nature of change. The weather, for instance, is a classic example. "The weather varies greatly throughout the year." Or consider how our moods can shift: "Her mood varies with the seasons." It's this constant flux, this movement from one state to another, that 'vary' and its forms so beautifully describe.
We also see 'vary' used when we're actively making something different. Imagine you're trying to spice up your cooking. You might decide to "vary your diet more." Here, you are the subject, and you are actively changing your diet. The sentence structure shifts, but the core meaning of change remains.
Sometimes, the nuances can get a bit deeper. In music, 'vary' can mean to create variations on a theme. In biology, it touches on the idea of mutation or difference within a species. These are extensions of the core concept: things are not uniform; they are different, they change, they adapt.
So, the next time you're faced with that little choice, just ask yourself: Is my subject singular and am I talking about the present? If yes, you're likely looking at 'varies'. If the subject is plural, or you're talking about a general truth or past action, 'vary' (or its past tense 'varied') is probably your friend. It's all about keeping that natural flow, making sure your words are as clear and as fitting as the situation they describe.
