Yes/no questions
Chinese has two ways of asking yes/no questions. You can simple add 吗 (ma) after the declarative sentence.
Example:
他住在北京. (Tā zhù zài Běijīng.) 'He lives in Beijing.'
他住在北京吗? (Tā zhù zài Běijīng ma?) 'Does he live in Beijing?'
你有弟弟吗? (Nǐ yǒu dìdi ma?) 'Do you have a younger brother?'
Alternatively you can use the construction: verb 不/没 verb to form the question:
他住不住在北京? (Tā zhù bù zhù zài Běijīng?)
你有没有弟弟? (Nǐ yǒu méi yǒu dìdi?)
Note: 没 is used to negate the verb 有 (yǒu) 'to have'.
Both forms can be used interchangeably. 吗 questions tend to expect an affermative answer, while 'verb 不/没 verb' questions make no such assumption.