is this her pencil box?改为陈述句

is this her pencil box?改为陈述句 Is this pencil box?(改为陈述句) This is her pencil box.(改为否定句) 改为复句this is my pencil box Is this your pencil?改为陈述句+复数 Her pencil box is under the sofa.改为一般疑问句 Her watch is in the pencil box .(改为一般疑问句) it is her pencil box.改为否定句 this is my pencil box.改为否定句 This is his pencil-box.改为复数句子怎么改? This is my pencil-box 改为同义句 This is a pencil box 改为一般疑问句