在 Zài
哪里 Nǎlǐ
这里 Zhèlǐ
那里 Nàlǐ

哪 Pronounced like “nah”
里 Pronounced like “lee”
在 Pronounced like “z-eye”

哪 means which
里 means in, within, inner
哪里 means where
这里 means here
那里 means there
在 shows location

Stating location generally goes before the verb and directly after the subject. 在 zài is generally the word used to link the subject to a location and it follows this format.

Subject + 在 + Location + Verb + Object

*你在哪里？
Nǐ zài nǎlǐ?
Where are you?

我在这里。
Wǒ zài zhèlǐ.
I am here.

台老师在哪里?
Tái lǎoshī zài nǎlǐ?
Where is teacher Tai?

台老师在那里。
Tái lǎoshī zài nàlǐ.
Teacher Tai is there.

李友，你在哪里吃晚饭？
Li you, nǐ zài nǎlǐ chī wǎnfàn?
Liyou, where do you eat dinner?

我在家吃晚饭。
Wǒ zàijiā chī wǎnfàn.
I eat dinner at home.

*In the first example, there’s no object because an object is not required. This brings up an interesting sentence structure known as Topic + Comment. It will be covered later.