Usages of yídìng
虽然 他 很 忙， 但是 他 一定 会 来。suīrán tā hěn máng, dànshì tā yídìng huì lái.
Although he is very busy, he will definitely come.
谢谢 你， 我 一定 请 你 吃 晚饭。xièxie nǐ, wǒ yídìng qǐng nǐ chī wǎnfàn.
Thank you; I will definitely treat you to dinner.
老师 说 只要 我们 每天 认真 复习， 中文 水平 一定 会 提高， 这样 大家 就 更 有 信心 了。lǎoshī shuō zhǐyào wǒmen měitiān rènzhēn fùxí, zhōngwén shuǐpíng yídìng huì tígāo, zhèyàng dàjiā jiù gèng yǒu xìnxīn le.
The teacher said that as long as we review carefully every day, our Chinese level will definitely improve, and then everyone will be more confident.
Elon.io is an online learning platform
We have an entire course teaching Chinese grammar and vocabulary.