2. I think it best that you should stay with us.

分析：it是形式宾语，best是宾语补足语，that you should stay with us是真正的宾语。

1. He felt it his duty to mention this to her.

分析：it是形式宾语，his duty是宾语补足语，to mention this to her是真正的宾语。

11. He watched the piano carried upstairs. (过去分词作宾补)

注意：在这个结构中，可以出现用it作形式上的宾语，把真正的宾语放在宾语补足语的后面。在此结构中，宾语常常是动词不定式或宾语从句。

10. I saw her chatting with Nancy. (现在分词作宾补)

9. Did you notice him come in？(不带to的不定式作宾补)

8. He believed her to be telling the truth. (不定式的进行式作宾补)

7. He believed them to have discussed the problem. (不定式的完成式作宾补)

6. We thought him to be an honest man. (tobe作宾补)

5. What do you advise me to do？(不定式作宾补)

4. We went to here house but found her out. (副词作宾补)