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Expressing certainty or obligation with 一定 (yīdìng)
Emphasis
Obligation & Necessity
Structure
一定 + 要 + Verb
Explanation
一定 (yīdìng) is an adverb meaning "certainly," "definitely," or "must." It expresses strong conviction or an emphatic sense of obligation. When used with 要, as in 一定要保护 (must protect), it reinforces the speaker's determination or insistence.
Examples
明天一定要早点起床，别迟到了。
Míngtiān yīdìng yào zǎodiǎn qǐchuáng, bié chídào le.
You must get up early tomorrow—don't be late.
我一定会完成这个任务的。
Wǒ yīdìng huì wánchéng zhège rènwù de.
I will definitely complete this task.
你一定要注意安全，路上小心。
Nǐ yīdìng yào zhùyì ānquán, lùshàng xiǎoxīn.
You must pay attention to safety—be careful on the road.