为什么"It is under the table."变成复数时table要加s?老师讲的跟练习册上不一样啊.

It is under the sofa? there ___an eraser under the desk.Is it yours?为什么 it'is under the box.是什么意思 under the it desk is怎么排列 Life under the sea is c_____.It is beatiful What is under the desk?-_________.A.It is a rulWhat is under the desk?-_________.A.It is a rulerB.That is a catC.They are red boxes选哪个?语法是什么?为什么选这个?急, it’s under the It under the chair is连词成句 the it table is under连词成句 It is under the chair.改为一般疑问句 连词成句 is it the under chair(.) It is fun under the sun.哪儿错了? It is fun under the sun.哪儿错了? is the desk under it连词成句 my pen is under the chair,please()it(). It is distributed under the license.怎么翻译? anyhow,it is the water under the brige nowit is the water under the brige now请问这是一句谚语吗? Is it under the bed?变为复数句时,当中的bed是否要变为beds?为什么.