区分三大非谓语动词间的句法功能
  
人教版 Book 7 Unit 3  语法  1课时
动词不定式基本形式
to do
to be done
to have done
to have been done
to be doing
\
to have been doing
\
分词/动名词基本形式
doing
being done
having done
having been done
\
done