1(before a noun) Do (you, they etc) have ...?
2Is there a ...?
3(before a verb) Did (you, they etc) (verb, infinitive)?
4Have (you, they etc) (verb, past participle)?
Examples
wǒ我bú不zài在de的shí hou时候yǒu méi yǒu有没有rén人lái来？
我不在的时候有没有人来？
Did anyone come in my absence?
有没有人要养可爱的小猫？
Is there anyone who wants to keep the cute kitten?
有没有比这些稍微大一点的？
Do you have one a little bigger than these?