Is it okay to not put "a" in front of "great opportunity"?

Native speaker’s answer
Rebecca
No, it does not make sense to remove the indefinite article "a" here from this sentence. Articles are used to modify nouns. In this case, the adjective "great" modifies the noun "opportunity". However, articles must still always be used before adjectives which modify nouns. Ex: She is a sweet dog. Ex: It was a long day.