再三【zàisān】

再三 says an action was repeated on purpose, because once wasn't enough. The verb is usually two syllables and about speaking or deciding: 嘱咐, 强调, 提醒, 要求, 考虑, 感谢. It's neutral to formal.

After the verb

With 考虑 and 犹豫, 再三 can follow the verb. The phrase then sets the scene for a decision, and the next clause gives it.

经过再三考虑 and 在…再三要求下 are the written forms of the same idea.

Not for things that keep going wrong

再三 is about effort. Something that keeps happening without anyone meaning it to – a mistake, being late – takes 一再 or 经常.

• × 他再三迟到 → 他经常迟到
• × 这个问题再三出现 → 这个问题一再出现