The book is in front of the pen.=The pen is_____ the book.

问题描述:

The book is in front of the pen.=The pen is_____ the book.

behind 在。。。之后

behind 书在笔前面 笔就在书后面咯

填介词behind

你好,有两种填法:
一、The pen is behind the book.
二、The pen is in back of the book.
希望帮助到你!