Articles are not decorative.

I keep seeing "I have a apple" or "She is teacher" in posts where the writer clearly knows the sentence structure. It is not a small thing. In a Band 7 essay or a work email, that missing "an" or "the" quietly changes how the reader trusts you. It is not about sounding perfect; it is about not forcing the reader to guess. The rule is learnable. Correct it once, in context, and it stays corrected. Untrained, it stays a lifelong pattern that costs you marks and credibility. "They understood me" is the lowest bar there is.