Articles (a, an and the) are tricky. Non-native English speakers struggle with knowing when and when not to use them. Native speakers instinctively know, but most cannot consciously articulate the rules they’re unconsciously following. (Why is it “plants release oxygen into the air” and not “plants release the oxygen into air”? Why is “the tiger is a noble beast” correct, when you’re not talking about one specific tiger?)
Grammar-checking software is bad at using articles correctly, too. This is particularly unhelpful for the non-native speakers who might be relying on it to correct their own shaky grasp of article usage.
Here are some examples I’ve found in the course of my work.
I edited a whole chapter about space, which the software kept wanting to change to “a space” or “the space”.
It complained about a missing article in “if blue light is absorbed”. This must be a new branch of science dealing with molecules that absorb blue table lamps!
In “the heat was sufficient to turn the sand into glass”, it wanted to change “glass” to “a glass”. First, scientific processes were absorbing lamps (“a blue light”), and now they’re creating tableware (“a glass”).
(A friend pointed out, based on an earlier draft of this post, that “a glass” is actually a thing in science, meaning any glass-like amorphous solid – in the same way that in science you can have “a sugar”, “a salt” or “an alcohol”, which are broader categories than the things normally called sugar, salt and alcohol. But I’m pretty sure that the author of this school-level textbook simply meant “glass”, the mass noun, silicate glass, which windows and drinking vessels are made of. Also, the software doesn’t accept “a sugar”, “a salt” or “an alcohol”, as they are mass nouns in non-scientific English.)
In “the reaction will reach equilibrium by producing more nitrogen(IV) oxide”, it wanted to insert an article before “more”. I don’t understand why.
In “it takes time to process the raw materials”, it wanted to insert an article before “time”. This software is generally rubbish at coping with article-less nouns (like “space” in the example above), but this case is especially bad because it should know that “it takes time” is a common phrase.