Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings

should; ought to; used as a shortened form of 应该 yīng​gāi or 应当 yīng​dāng

Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings

to answer; to respond; to reply to a call or a question