英语高手进呀

This is pencil case.
错， 因为没有冠词。
This is a pencil case.

That's a book.A book is on the deask.
错，冠词应为定冠词the，因为前文中提到了book，所以后文中的book是确定的
That's a book.The book is on the deask.

This is a pencil case
That's a book.The book is on the deask.

都有问题，
This is a pencil case.这是一个铅笔盒。
That's a book.The book is on the desk. 那是一本书。它被放在课桌上。

都错
第一个少冠词
第二个是deask
明白？？？？？？

This is a pencil case.
That's a book. A book is on the desk.