一定 yī dìng surely; certainly; definitelyfixed; settleda certain …; a given … Example sentences 要是你不早点睡,明天一定会迟到。 yàoshi nǐ bù zǎodiǎn shuì, míngtiān yīdìng huì chídào. If you don't go sleep early, you will definitely be late tomorrow 要是你每天练习汉语,不久以后一定可以说得很好的! yàoshi nǐ měitiān liànxí hànyǔ, bùjiǔ yǐhòu yīdìng kěyǐ shuō de hěn hǎo de! If you practice Mandarin every day, you definitely can speak Mandarin fluently in a short time