这 zhe
Pronounced like “just”

那 na
Pronounced like “not”

这 means this
那 means that

这 and 那 are the two words used when you want to address something relatively close to you or quickly. Remember in the Measure Word post that I spoke of cases where you do not require numbers in front of the measure word. 这 and 那 are two of these cases. *They always require a measure word after them when describing an object.

这本书。
Zhe ben shu.
This book.

这纸张。
Zhe zhi zhang.
This paper.

那杯水。
Na bei shui.
That cup of water.

那个人是我的爸爸。
Na ge ren shi wô de baba.
That person is my father.

水 shui
Pronounced like “shway”

水 means water.

* Do remember that 这 and 那 require measure words when describing an object. Saying 这是 and 那是 are correct.