Sentence-final particles 吧, 啊, 呢
助词 / particles (语气助词)
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
Sentence + 吧 / 啊 / 呢
These little particles set the sentence's tone:
吧: suggestion (我们走吧 = let's go), or an assumption you want confirmed (你是法国人吧？ = you're French, right?).
啊: exclamation, warmth, emphasis (好啊！= sure!; 多漂亮啊！= how beautiful!). It often becomes 呀 after a vowel.
呢: bounce-back question (我很好，你呢？= and you?), where's…? (我的手机呢？), or ongoing action (他在吃饭呢).
Examples
我们一起去看烟花吧！
Wǒmen yìqǐ qù kàn yānhuā ba!Let's go and watch the fireworks together!
A：明天来我家吃饭吧？B：好啊！
A: Míngtiān lái wǒ jiā chī fàn ba? B: Hǎo a!A: Come over for dinner tomorrow? B: Sure!
我春节回老家，你呢？
Wǒ Chūnjié huí lǎojiā, nǐ ne?I'm going back to my hometown for New Year, how about you?
今天的月亮多圆啊！
Jīntiān de yuèliang duō yuán a!How round the moon is tonight!
Common mistakes
吧 questions take no extra 吗: ✗ 你是法国人吧吗？ → ✓ 你是法国人吧？
呢 doesn't replace 吗: ✗ 你好呢？ → ✓ 你好吗？