陈述部分的主语为不定代词something,anything,nothing,everything时,问句部分的主语用it.如：
①Something is wrong with the computer,isn’t it?②Nothing has happened to them,has it?
陈述部分的主语为不定代词somebody(someone),anybody(anyone),nobody(no one),everybody(everyone)时,问句部分的主语用he或 they,这时问句动词的数应和he或 they一致.如：
①Someone has taken the seat,hasn’t he?
②Everyone has done their best in the game,haven’t they?