Among them, matter is a noun, which means "problem; In this sentence pattern, the article the must be added before matter. You can also use what's wrong with (someone) or what's wrong with (someone) to express the same meaning.
Keywords: substance
Matter is an intransitive verb, which basically means "very important to people" and "very important and serious".
Matter is often used in the structure where it is the formal subject, and its real subject is generally the present participle phrase, that clause, wh- clause or if/where clause.
Should you say no when you answer someone's apology? Matt, no. The stakes are high.
Matter is a static verb and is generally not used in the progressive aspect.