请帮我解析一下这句英文谢谢

题目

请帮我解析一下这句英文谢谢
The roads are very difficult to ride on.
问:可转换为It is very difficult to ride on the roads.
麻烦帮我分析句子成分，原句中to ride on 是做真正主语还是目的状语。

答案

请注意are 在这里是be动词,very difficult to ride on 是表语.
to ride on 是不定式短语 用来修饰 ,very difficult 的,是表语补足语
记住这个句型主系表结构,而不是主谓宾结构!它的动词are 是系动词!