假如正确，这个结构表示什么？期盼老师的指点。
It can be that...如此的句子，除去刘老师所说的it为人称代词，指代前文提及的内容，that为表语从句外，确实还有另一种状况，即it为形式主语，can be中的be为不及物动词，意为exist 或 happen，that引导的是真的主语从句。can表示可能性，can be 这种情态意义可以改用is possible替换。即 It can be that... = It is possible that...。it为形式主语，that引导外置主语从句。以下二个句子来自COCA语料库。仔细读这二段文字，大家会发现，it can be that...句子中，it并没指代前文任何内容，it只不过一个虚指主语（形式主语）。
If a country is losing a creative young generation, they have not had the means to reproduce itself. This will be a vicious cycle of degradation, of decline of the society. Its not just a problem. Its the most difficult problem that Greece isfacing today. I call this the annihilation of a generation. They have no jobs. They will not have a generation of creative entrepreneurs in Greece.ItcanbethatGreeks and the Greek society will decline totally, as a failed state, as a failed society.
It is also true that not everyone can be a disciple, since discipleship also presupposes a special call from Jesus. It does not depend on the will of the individual.Itcanbethatsomeone wants to follow Jesus but is not made his disciple.
网友给出的以下二个词典例句中，it也是形式主语，that从句为真的主语从句。can be可以改写为is/was possible, 意义相同。
Could it be that it was written wrongly?
= Was it possible that it was written wrongly?
《新英汉大辞典》
It could well be that he has a real vocation.
It was really possible that he has a real vocation.
对于it can be that...的这种理解可以圆满地讲解as can/could be这种比较结构。比如：
He ran as fast as could be. 比较分句补全后为：
= He ran as fast as it could be that he would.
= He ran as fast as possible.
= He ran as fast as was possible.
= He ran as fast as it was possible that he would.
即as分句省略了形式主语it和外置that从句。
