Tom family is eating lunch 为什么要用is

Tom family is eating lunch 为什么要用is tom is eating lunch(改为一般疑问句) He is eating lunch.(用they替换he) Jenny is eating lunch.(变一般疑问句) He is eating lunch.(改为复数) （ ） （ ） lunch. Her aunt is eating an apple every day.为什么要用is eating he is eating his lunch同 he is eating lunch有什么区别 His family is/are eating dinner now 1.Tom is having lunch at hone.(用just now改写） Tom ___ lunch at And Daming is eating lunch and lying in the sun. He is eating lunch at home.改成特殊疑问句. I is eating lunch变成一般疑问句怎么变?