The most common use of 难 is as a simple adjective, usually preceded by an adverb like 很 (hěn), meaning “very.” `Subject + 很 (hěn) + 难 (nán)` It describes tasks, subjects, problems, or situations that are hard to do or understand.
难 is frequently placed before a verb to create a new adjective describing an unpleasant or difficult sensory experience. This is an extremely common and important pattern.
The structure 难道 (nándào)…吗 (ma)? is used to form a strong rhetorical question, similar to “Could it really be that…?” or “Don't you…?” in English. It expresses surprise or disbelief.