How to decide whether the definite article is needed before plural nouns - Difficult cases

Question

I've heard plural nouns sometimes need to be preceded by the definite article "the," and at some other times, no article is needed (the "zero article" case). I have a question on how to decide when to use which case.

First, let me mention that in some cases, the decision as to whether or not the definite article is needed is very simple to me. For example, it is 100% clear to me that the definite article is needed in the following example:

Example 1: I liked the books you sent me last month.

Similarly, it is 100% clear to me that the definite article is not needed in the following example:

Example 2: Responsible citizens should respect the law.

Despite this knowledge, I badly get stuck in some cases. Given the same sentence, one day, it seems to me like the definite article is needed, and on a different day, I come up with the opposite verdict (zero article). Here is one example:

Example 3: Does the quality of the(?) items selected along the way matter?

I would appreciate it if you could kindly help me with the following questions:

1. Do you think that the definite article "the" is needed before "items" in the above sentence?
2. Can you let me know the thought process you go through to answer Question 1?
3. Finally, I wonder if it is as easy for you to resolve Example 3 as Examples 1 and 2, or do you also find it more challenging to resolve Example 3? I am trying to get a sense of how the world of native speakers looks like when it comes to identifying zero article cases.

Answer 1

1. It's correct both with and without "the"

2. Unfortunately, as a native speaker, my thought process is to try it both ways and determine if it is correct by simply knowing.

3. It was a bit harder because I had to try it both ways, and usually it's only correct one way, or it's significantly better one way, but in this example, it feels 100% natural both ways.

So, all of that is probably not helpful to you, so I'll break it down as an English teacher, rather than as a native speaker.

The first thing I tell students struggling with article usage is that it's one of the three hardest things to get right in English (along with preposition choice and phrasal verb meanings). There are so many tiny little rules that only apply in certain very specific contexts, and sometimes only apply to an arbitrary subset of words. Most learners never learn all of them and make mistakes with articles forever. And that's probably fine since there's so few situations in life where anybody needs native proficiency.

Enough with the pep talk. Let's get down to analyzing this sentence.

A noun with a zero-article means the noun in general. In sentence 3, if there's a zero-article, "items" by itself means "items in general", but then it is specified by the reduced relative clause "selected along the way". A noun cannot be both general and specified, so it becomes clear that the zero-article doesn't modify "items" alone, but modifies the entire noun phrase, "items selected along the way". This makes sense, because we can talk in general about "items selected along the way".

A noun with "the" means the noun is being or has been specified. In sentence 3, it has not been specified in a previous context, so it must be specified in the sentence itself. The reduced relative clause, "selected along the way", specifies which items, so "the" applies to "items", and then "selected along the way" provides the specification.

So one way, the noun phrase in Sentence 3 means "the items selected along the way -- as opposed to other items not selected along the way", and the other way it means, "items selected along the way in general", without contrast to other items. The meanings are so similar, it's likely both are correct for the context. Using "the" would be preferred (only preferred, not required) if the context distinguished between items selected along the way, and other kinds of items, like items selected at other times, or items not selected at all.

Hopefully, that illuminates things a little bit.