That is a pencil box 这句话哪儿错了

That is a pencil box 这句话哪儿错了 That is a pencil box（改为否定） That is my a pencil-box.改病句 This is a pencil box.对a pencil box 提问 This is a pencil box.(对” a pencil box”提问 ) Is that your pencil-box?后一句是什么 That is a red pencil box.()That is a red pencil box.(改为否定句)____________________________.Is this your baseball?(作否定回答)___________________________. That is my pencil box改为一般疑问句 that is her pencil—box(改复数句) This pencil box is _____ (nice) than that one. That is her pencil box对her提问 Is that a pencil s___? are the pens (in your pencil box)? 做否定回答 that is a radio. (用some替换a） A pen is on a pencil-box.【改为同义句】 This is a pencil box 改为一般疑问句 Is's a pencil-box.改为复数句 It is a red pencil box.变成复数形式. this is a pencil-box这个句子有什么错