A：your
B：yours
C：you
① What are you doing? ____ A. No，she isn't.
② What is your mum doing? ____ B. Yes I am.
③ Can I use your pen? ____ C. I'm cleaning my room.
④ Is Sarah reading a book? ____ D. She is cooking fish.
⑤ Are yoy doing homework? ____ E. Sure.
根据图形回答问题：4号图形的面积是3号图形的____倍
