Do you like football?football后为什么不需要加“s”

Do you like football?football后为什么不需要加“s” DO you like football? Do you like playing football? do后面加动词原形那为什么是Do you like playing football?play为什么要加ing I like foorball . 为什么football不加s Does your mother like football football用不用加s do you like-----（some）football player Do you like play football.改错 英语What's your name?和do you like football?和What do you you us Tom likes playing football 这里play为什么要加ing 还有like为什么加S three boys like playing football中的like为什么不加s I know you like football.What ( ) sports do you like?