who is it speaking?it‘s TOM ---------这句中为什么用it,tom不是一个人门

Who's that?A It's Tom BThis is Tom who is it?选择,A.I’m tom.B.It’s tom. who is flying a kite 回答It's tom 选择：1.This is Tom speaking.Who's__calling? a.this b.that c.it Tom’s bike is broken.It needs (repairing)为什么要填repairing,不是被动 1.it must be Tom’s.2.it is Tom’s都对Tom’s画线,并选择who whose whom ruler is it?it is Tom＇s ruler. It is Tom's brithday ,Tom is twenty,but it is his fifth brit It's Tom 的问句 Whose shirt is this?____ a.It's me b.It's Tom c.It's Tom's this is tom,___did it （ ）Tom's Tom,look()the dog behind the door Is it yous?No,it(