动名词作主语顾名思义,就是动名词充当主语,动词从某种意义上讲,已经失去动词的性质了.有表示“常态、规律性”的意思
例：swimming is my favorite sports.
不定式作主语,表示动作未完成.
to go out this afternoon is impossible for me because i have a lot of homework to do .
仅为个人的教学实习经验和实践理解,不是专业解释,进攻参考,但本人觉得还是做题时候还是多好用的.