Hello! 你好! (nǐ hǎo)

Thank you! 谢谢! (xiè xie)

I'm sorry. 对不起。 (duì bù qǐ)

Bye! 再见! (zài jiàn)

You're welcome. 不客气。 (bù kè qì)

It's OK. / Not a problem. 没关系。(méi guān xì)

See you next week! 下星期见! (xià xīng qí jiàn

See you next week! 下周见! (xià zhōu jiàn) 

See you tomorrow! 明天见! (míng tiān jiàn)

Good morning! 早上好! (zǎo shàng hǎo)

Please wait. 请稍等。(qǐng shāo děng)

Please sit. 请坐。(qǐng zuò)

Q: Did you bring your homework? 你带作业了吗？(nǐ dài zuò yè le ma)

A: Yes (I brought it). 带了。(dài le)

Q: Did you bring your homework? 你带作业了吗？(nǐ dài zuò yè le ma)

A: No (I didn't bring it). 没带。(méi dài)

Q: Did you bring your homework? 我给你改作业好吗？(wǒ gěi nǐ gǎi zuò yè hǎo ma)

A: OK. 好。(hǎo)

Q: Where's your homework? 你的作业呢？(nǐ de zuò yè ne)

A: It's right here. 在这里。(zài zhè lǐ)

I forgot. 我忘了。(wǒ wàng le)

No. 不。(bù)

I want to go to the bathroom. 我要去厕所。(wǒ yào qù cè suǒ)

I want to drink water. 我要喝水。(wǒ yào hē shuǐ)

I want to eat crackers. 我要吃饼干。(wǒ yào chī bǐng gān)

I'm hungry. 我饿了。(wǒ è le)

I'm full (with food). 我饱了。(wǒ bǎo le)

I like it. 我喜欢。(wǒ xǐ huān)

I'm tired. 我累了。(wǒ lèi le)

I don't like it. 我不喜欢。(wǒ bù xǐ huān)

Where is [it/someone/something]? ...在哪里？(zài nǎ lǐ)

Please help me! 请帮我! (qǐng bāng wǒ)