那：it is a pen怎么改成复数形式

那：it is a pen怎么改成复数形式 改成复数形式．1．Is that a bus?2.What's thia?It's a box.3.Where is the pen?It's in the desk. It is a pen.的复数形式是什么? it is a key hes is a bay 怎么改成复数 英语复数形式it this a book,it is a pen,there is a book,以上改成复数形式.those are chair,what are these,以上改成单数is,coat,his,where连词成句，pen,book,watch,foot,man,woman,family,boy,child,girl复数形式，用正确形式 改成复数句.What is it?It's a box.改成单数句.The children are YOUNG Pioneers.改成复数句,并作肯定回答.Is this a red pen?改成复数句,并作否定回答Is that an English book?改为单数句Those are apples改为单数句Those a This is a pen变为复数句,怎么变 It is my pen.(改为复数形式) is it yellow 改成复数形式怎么改 It's a calculator改为复数形式It's a pen.It's my key.That's a clock.It's her book都改成复数形式 it is a mouse (改成复数句） It is a bowl of rice 改成复数句 It’s his pen.怎么变复数 this is my pen pal改成复数形式 that is my good pen friend 改成复数 把英文句子改成复数what is it?it's a mirror?it's a bus?请该为复数,怎么改 It's a pen改成否定句 this is pen?怎么改成一般疑问句