This is sam.<改为否定句>

This is sam.<改为否定句> lt is an orange 改为否定句 Is Tom smarter than Sam?改为否定句 sam is tall改为否定句,句意不变 This is Sam's friend .变否定句 lt is hot in summer 改为否定句怎么改 lt is Luck's dictionary. 改为否定句谢谢帮助 this is my friend.(改为否定句) This is my grandmother.改为否定句 This is my father()改为否定句 This is my room 改为否定句 is this your father?改为否定形式 This is my ruler (改为否定句) This is an eraser.(改为否定句) this is a map.(改为否定句) This is my siste 改为否定句 This is my room 改为否定句 This is an eraser.(改为否定句)