It's time _us to go to school横线上介词为什么for?

It's time _us to go to school横线上介词为什么for? It's time to go It's time to go to school It's time to go to the It's time to go bed Ready set go It's time to it’s time 【】【go】 to bed now it’s time 【】【go】 to bed now画线提问it’s time 【】【go】 to bed now can you please spend_explaining it _us?A sometimes to B some time to C some times for Dsometime for It' time to go. It's time to school .Let's go. It's time to go to school.同义句! It's time to go to school.改成同义句 go,it's,to,time,to,school连词成句 It's time to go to school.(同义词转换） It's time to go to home怎么改 同义句小学英语It's time to go to school it's time to go to bed翻译成汉语