You are the man whom I am looking forward to seeing. （动名词的宾语）

This is the book that I am interested in reading.（动名词的宾语）

The book that I've spent a month reading is very interesting.（现在分词的宾语）

Arabic is a language that I found it is difficult to learn.（不定式的宾语）

关系代词作定语从句中另外一个从句的宾语：

We havr a problem, which we will be grateful if you can help to resolve.

which 作 if 从句 resolve 的宾语。

我们有一个问题，如果你能帮忙解决，我们将不胜感激。