我就知道。(Wǒ jiù zhīdao.)I indeed figured (that) before.

Explanation

“我就知道”这个短句通常用来表示说话人已经猜测到某种情况会发生或是事实与说话人所猜想的一致。“就”有表示强调的意思。这个短句后面通常要叙述说话人所猜测的内容。
“我就知道” often indicates that the speaker has speculated what would happen or the fact is as the same as what the speaker has speculated. “jiu” means “just or indeed. A short sentence which indicates what the speaker speculated usually follows it.

Words:

猜测cāicè:speculate;
强调qiánɡdiào:emphasi.

Sentences

1、Jiă: Jīntiān de wănhuì wǒ xiăng chuān wǒ zuì xǐhuan de nà tiáo qúnzi.
甲:今天的晚会我想穿我最喜欢的那条裙子。
A: I want to wear the skirt that I like the best in the party tonight .

Yǐ: Wǒ jiù zhīdao nǐ huì chuān nàtiáo qúnzi。
乙:我就知道你会穿那条裙子。
B: I indeed figured that you will wear it.

2、Jiă: Jīntiān wănshang wǒ bāng nǐ yìqǐ wánchéng lăoshī jiāogěi nǐ de rènwu ba!
甲:今天晚上我帮你一起完成老师交给你的任务吧!
A: I will help you finish the assignment from the teacher.

Yǐ: Tài hăo le! Wǒ jiù zhīdao nǐ yídìng huì bāng wǒ de!
乙:太好了!我就知道你一定会帮我的!
B: Great! I indeed figured you will help me!

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