练习：辨别主语（形式主语和真正主语)
It is necessary to get water from wet to dry places. It is necessary getting water from wet to dry places. Getting water from wet to dry places is necessary.
Please remember to post the letter for me. I remember posting the letter.
意义明显不一样，如remember, forget, regret, mean, stop, try, want, need
He forgot to write to me. I’ll never forget visiting London for the first time. I regret to say that I cannot go with you. She regretted missing the report.
escape, deny, risk, suggest等后能接 动词-ing形式作宾语，而不能接动 词不定式。如： We’re considering paying a visit to
the Science Museum.
2. 有些短语如can’t help, be used to, end up, feel like, lead to, be busy, be tired of, be fond of, be afraid of, be proud of, think of / about, put off, keep on, insist on, be good at, give up等后常接名词、 代词或动词-ing形式作宾语。如：
