"No tiene un gato" is a correct sentence. But it needs context as it can be translated 3 ways. Here are the ways with their identifying pronouns:
Él no tiene un gato. - He does not have a cat.
Ella no tiene un gato. - She does not have a cat.
Usted no tiene un gato. - You [formal] do not have a cat.
It means do you have or does it contain.
"Me gusta gato hombre" translates to "I like cat man" in English.
Tiene
"Gato" is a Spanish and Portuguese word for Cat.The cat
Él tiene means: he has. It is phrase and not a complete sentence.
You(polite, singular)/he/she/it does not have
"i" its the past tense for the verb tiene "to have"
Usted tiene is a sentence fragment that means "you have". This is a formal statement. When speaking informally the fragment would be "Tú tienes"
"tiene siete dias" means "has seven days"
Means "My cat has the biggest balls" PELOTUDO DE MIERDA xD
Tiene / tienen / tienes / tenéis
Each has.