That is an apple的复数是什么

that is an apple tree 改复数句 Is that an orange的复数形式是什么? apple复数apple的复数是什么 that is an red apple 变复数1.This is a knife2.That is an apple tree3.He is a policem apple的复数是什么 This is an apple.that is a pen.改复数形式 this is an apple and that is a 写出复数句. this is an apple.改成复数形式 This is an apple 变为复数句子 That's a ruler.对 a ruler 提问.Is this an apple?改为复数句子. That apple is his.(改为复数)