After I got up, I noticed a post that was posted byon Reddit about someone who wanted to know how to use the auxiliary word “了”。Chinese people who learn English think that it’s difficult to choose whether to use the article A andor the article THE, but native English speakers can easily use them like they have some magic.

You must put the definite article before the word "article" in this sentence. I feel that it is necessary. I think this is because there are only two articles, the definite article and the indefinite article. You must choose the one or the other.

There are several other ways you could say it. 1. It is difficult to choose whether to use an A or a THE. 2. It is difficult to choose whether to use A's or THE's. 3. It is difficult to choose whether to use A or THE.

You may not say, however, "It is difficult to choose whether to use article A or THE."

You must use "or" instead of "and" because you may not choose to use both A and THE.

But no matter how much time Chinese learners spend learning it or how many times native English speakers explain it to them, Chinese learners still make mistakes on how to use articles.

"Explain" is a transitive verb so it must have an object.