Here are the pronunciations:
* First tone (mā): dōu (like "doe" with a slightly higher pitch)
* Second tone (má): dóu (like "doe" with a rising tone)
* Third tone (mǎ): dǒu (like "doe" with a dip in the middle and then a rise)
* Fourth tone (mà): dòu (like "doe" with a falling tone)
To know how to pronounce "dou" in a specific word, you need to know the tone of the character in that word.
For example:
* 都 (dōu): means "all" or "both" and has the first tone.
* 豆 (dòu): means "bean" and has the fourth tone.
If you're unsure about the tone, it's best to look it up in a Chinese dictionary or online resources.