The pencil isn’t m___,it's my sister

The pencil isn’t m___,it's my sister Gina isn' t my sister. She's 介词填空：The pencil isn't yours.It's mine.Please give it back___ It isn't my sister or my brother,but still is the child of m --oh,it's beautiful pencil-box ,isn't it?--yes,it is ,It ___ The Eiffel Tower is made of m___ , it isn't a s___ building it's not my...和 it isn’t my. is this your pencil case?___a 、yes,it's b 、no,it isn't 填空：Is this____pencil case? No,It isn't my pencil case. this isn't ____ball,It's is under the chair.A.mine;he;My B.m 1.The classroom isn't busy.It's very q .2.My mother e taking (no,it isn't)(lt's a bike)(lt's a pencil case )(and what's t