I don't understand why do we have to put ''s'' at the end of the verb in this examples<br/><br/><i>Who own<u>s </u>this umbrella?Everybody use<u>s</u> it but nobody know<u>s</u> who own<u>s</u> it<br/>ordo you mind if I ask you a question?That depend<u>s</u> on the question.''<br/><br/>I understand that we put s or es in third person singular...please explain me sentences above <br/></i>