读句子，用am,is,are填空。
1.I_______aboy,you_______agirl,we________friends.
2.He________astudent,she_____astudent,too.They______students.
3.I_______helpfulathome,myfather_______helpful,too.
4.Mybrother_____tall,mysister_____short,butthey______all(都)thin.
【答案】1、 am , are , are 2、is , is , are 3、am , is 4、is , is , are
【解析】让学生牢记口诀：单数 is 复数are , 我用 am 你用are , is 连着he , she ,it .