吗, 呢, 吧: the sentence-final particles

Three tiny words that turn statements into questions, bounce questions back, and soften commands into suggestions.

吗 — the yes/no switch

Append 吗 to any statement and it becomes a yes/no question, word order untouched.

你是学生吗？

nǐ shì xuésheng ma?

Are you a student?

你会说中文吗？

nǐ huì shuō Zhōngwén ma?

Can you speak Chinese?

呢 returns a question without repeating it ("and you?"), and after a noun alone asks where it is.

我很好，你呢？

wǒ hěn hǎo, nǐ ne?

I'm fine — and you?

我的手机呢？

wǒ de shǒujī ne?

Where's my phone?

吧 rounds a command into a suggestion, and a statement into a "…, right?" — you believe it, you're checking.

我们走吧。

wǒmen zǒu ba.

Let's go.

你是法国人吧？

nǐ shì Fǎguó rén ba?

You're French, right?

Patterns stick when you meet them in sentences you can read. The app drills each one at i+1, scheduled by FSRS.