knapsack 和 backpack 的区别是什么?

knapsack 和 backpack 的区别是什么? happens和backpack是什么意思 Is his backpack on his desk?否定和肯定回答、 backpack音标 backpack是什么意思 backpack是什么意思 Is that her backpack?No,I think ___his backpack.___上填it's还是its?it's和its的用法? 用computergam和backpack分别写一个特殊疑问句和一般疑问句,都要答语 his baseball is in his backpack做一般疑问句 和回答 ［紧急求助］pencil和backpack的复数形式是什么? It is my backpack _your backpack Your backpack is where's my backpack? where is backpack Where's my backpack? BACKPACK什么意思 backpack啥意思 请问,backpack是什么意思?