别做白日梦了。(Bié zuò báirìmèng le.)Stop daydreaming!

Explanation

“做白日梦”指的是幻想一些不可能实现的事情。“别做白日梦了”一般用于劝告，告诉别人某种情况不可能存在或者某事不可能实现。
“做白日梦”means to fantasy something which can’t be realized. “别做白日梦了(bié zuò báirìmèng le)” is usually to advise somebody. It is to tell something doesn’t exist or will not be achieved.

words:

彩票cǎipiào:lottery tickets;
环球旅行huánqiú lǚxínɡ:travel all over world.

Sentences

1、Jiă: Wǒ xiǎng qù Hāfó Dàxué liúxué.
甲：我想去哈佛大学留学。
A: I want to go to study in Harvard.

Yǐ: Bié zuò báirìmèng le! Nǐ zhème bù nǔlì, shàng Hāfó shì bù kěnéng de.
乙：别做白日梦了!你这么不努力，上哈佛是不可能的。
B: Stop daydreaming! It is impossible for you not being hard-working.

2、Jiă: Wǒ xiǎng qù mǎi cǎipiào, rúguǒ zhòngle yí ge yì, wǒ jiù qù huánqiú lǚxíng.
甲：我想去买彩票，如果中了一个亿，我就去环球旅行。
A: I want to buy lottery tickets. If I won 100,000,000 Yuan, I would travel all over world.

Yǐ: Bié zuò báirìmèng le! Nǐ háishì hǎohao gōngzuò ba.
乙：别做白日梦了!你还是好好工作吧。
B: Stop daydreaming! You’d better work hard.

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