there is an eraser on the desk 对划线句提问 an eraser 划线

there is an eraser on the desk 对划线句提问 an eraser 划线 It is an eraser. It is an eraser? There is nothing in ________ of his hands and there is an eraser in ________ This is an eraser 对an eraser 提问 there ----------------- an eraser on the desk. there is an eraser on the desk.[改为发复数句] There is a pen and an eraser in the box否定句和一般疑问句和a pen and an eraser 划线提问 Is that an eraser?的回答 this is an eraser 改复数 It is an eraser in English. It is an orange eraser.改为复数 this is an eraser 变复数.快 This is an eraser.(改为否定句) This is an eraser.(改为否定句) It is an eraser .改为否定句 This is her an eraser.与This is her eraser.This is her an eraser.与This is her eraser.为什么不用“an”? This is eraser,eraser is inThis is eraser,eraser is in the pencil box.A.a;The B.an;The C.an;An D.the;The(对了,)