第1个回答 2009-08-05
1。It是形式主语， to learn english不定式是真正主语
2。不可以这么说:learn english is easy
但可以这么说:To learn english is easy.
第2个回答 2009-08-05
形式主语+谓语+形容词+不定式（真正主语）
不能，要把learn改为learning
只有动名词才能做主语
第3个回答 2009-08-05
第二句改为To learn English is easy
为了避免头重脚轻得感觉，所以用it做形式主语，习惯上这么用
第4个回答 2009-08-05
1.主语从句
2.learn变learning，因为动名词作主语，ing形式
第二部分：为了防止句子头重脚轻，通常把形式主语it放在主语位置，真正主语搁置于句末
（1）It is certain that he will win the match.
（2）It is true that he has made a very important discovery in chemistry.
（3）It is very likely that they will hold a meeting.
（4）It is strange that he should do that.
（5）It is important that we all should attend the meeting.
（6）It is strange that the man should have stuck to his silly ideas.
（7）It is a pity that we won't be able to go to the south to spend our summer vacation.
（8）It is still a mystery what caused the accident.
（9）It is said that he has gone to shanghai.(=He is said to have gone to shanghai)
（10）It is known to all that the gun powder was first invented by the Chinese.
（11）It is suggested that the work should be done with great care.
（12）It seems that he has seen the film.(=He seems to have seen the film)
（13）It happened that the two cheats were there. (=The two cheats happened to be there