Do you know who the pen belongs to?belong后为什么加s?

Do you know who-------- ( 发明 ) the telephone? 请问Do you konw who is the man还是Do you know who the man is Do you know who am Do you know the boy (who is ) called Tom?和 Do you know the boy (who is ) callingTom?的区别Do you know the boy (who is ) called Tom?和Do you know the boy (who is ) callingTom?的区别 do you know who was the first_________ hereAto reachBto arrive Do you know who is the a________ of this book? Do you know who the acticle is written _____? Do you know who is c____of the Helping Hands Club Do you know who is the co-founder of Apple? Do you know who _____(enter) the house just now Do you know who ____(inwent) the telephone? do you know who--------（invent） the tv set? Who do you know gave the fire a___? Who other do you know in the city do you know who the computer belongs todo you know who the computer belongs to?（同义句）do you know ____ the computer _____ do you know the sudent who is a girl of eightdo you know the student who is _______ _____________girl do you know the sudent who is a girl of eightdo you know the student who is ______ ________girl Do you know the girl who is in the red dress?Do you know the girl____ ____ ____ ___?