误The sentence is difficult to be understood.
正The sentence is difficult to understand.
析difficult用作表语,其后如用动词不定式,一般用主动结构,而不用被动结构。
他学习语言很吃力。误He is very difficult to learn languages.
正It's very difficult for him to learn languages.
这篇文章对我来说很难懂。误I am difficult to understand the article.
正It's difficult for me to understand the article.
析difficult表示“难的,困难的”,一般用来指物,不以“人”作主语,并且须用“It is/was difficult for sb to- v ”的结构。