the book is easy to understand.

[tulipflower]

Which one is correct?
The book is easy to understand.
The book is easy to be understood.

 

[Matthew Wai]

I would go for the first one.

 

[Raymott]

You can say, "The book is easily understood" but your first choice is still better.

 

[emsr2d2]

We might use "can be easily understood" if it's followed by a specific group of people.

I like this book. It can be easily understood by young children.
It's a great film. The dialogue is slow and clear so it can be easily understood by English learners.

 

[Matthew Wai]

Are the following incorrect?

It is easy to be understood.

I am easy to be understood.

I find it easy to be understood by others.

 

[Raymott]

Are the following incorrect?

Yes.

 

[engee30]

I'm speechless. All I'm left with to say is this: It is not easy to be understood by everybody.

 

[GoesStation]

Are the following incorrect?

The first and last are correct, though not terribly natural. The second, "I am easy to be understood," is incorrect.

 

[konungursvia]

Yes.

I find the third quite correct.

 

[Raymott]

OK, well it seems that there's a lot of disagreement about the usage among native speakers.
Does, "I find it easy to be understood by others" mean "I can easily make myself understood by others"? or "I find that I am easily understood by others"? If so, I'd use one of the latter two.

 

[Matthew Wai]

Is there a reason why 'adjective + passive infinitive' is ungrammatical?