When you're writing a sentence, you want the verb to agree with the subject. But sometimes, it can be tricky when you have a word like none as part of the subject. So I'm going to tell you how you can make sure that there's agreement in your sentence when you see the word none. There are different kinds of pronouns, some are singular, some are plural, and some swing both ways. They're like living in San Francisco in the 1960s and 70s. None is one of those words that swings both ways which means that sometimes it can be singular, and sometimes it can be plural, depending on the sentence. So when you have a sentence with the word none in it, like this one, I'm going to show you how you can decide whether you need the singular or the plural verb.
In this case, the verb in our sentence is has. And the subject in our sentence is none of my stamp collection. Now we're trying to figure out if the subject is singular or plural. Well, in this case, when you see the word none, and you know it swings both ways, you look at what comes next. In this case, it's stamp collection. If stamp collection is singular, which it is, you have a singular subject. None is functioning in a singular way. So, in this case, we need the singular verb has. None of my stamp collection has lost its value. It would be incorrect to say, None of my stamp collection have lost their value." Let me give you another example. So let's change this sentence to be a little bit different. Let's say, none of my stamps have lost their value. All right. So, in this case, our subject is plural. We see the word none, we know it swings both ways. So, we look at what comes next. And, in this case, what comes next is the word stamps, which is plural. So now, none of my stamps is plural. None is functioning in a plural way, and we need the plural verb to make sure that there's agreement. So that's why, in this sentence, we reach for the verb have, which is plural. None of my stamps have lost their value. In other words, it wouldn't be correct to say, "None of my stamps has lost their value." So I hope that this makes it a little bit clearer about how to make sure that there's agreement in your sentence when you come across that tricky word, none.