Why a plural form :whith that promotion ... THEY included free courses ??
What plural form do you mean: They?
Or: free courses?
Please explain your question in another way.
From frederique19: Why a plural form :whith that promotion ... THEY included free courses ??
I'm not sure I understand the context exactly (you should give us the subject of the sentence so that we can see what THEY is referring to).
I'll assume that THEY is confusing you because there was a singular subject established earlier. In English, THEY is often used as a 'gender-neutral' pronoun. In order to avoid specifying the sex or gender of something, we use 'they' to include both sexes.
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