这本书对我们来说太难了 英文l’m afraid……来回答

This book is too deep for us.

I'm afraid that the book\it\this is too difficult to me!
根据上文是否提到此书来选择，提到了用前两个都可以，没有就用第三个。希望帮到你!

This book is too difficult for us.

I’m afraid that this book is really difficult for us.
如果句型用too difficult一般后面跟to do sth.意思就是太难了以至于我们不能做某事。（英语表达中不到一定程度不经常用too）
如果句型用so difficult一般后面跟that+从句 意思是如此难以至于我们...
如果只是单纯地表示太难，really挺合适。

I'm afraid that this book is too difficult for us.

this book is too difficult for us.
this book for us is too difficult.