英语语法问题求解。。。谢谢了
1.because是从属连词，表示因果关系，可以引导原因状语从句，表语从句和主语从句。
2.it此处是普通代词，指代前文that。
it作为形式主语只是为满足语法上的需要，避免句子头重脚轻，它代替的是句子的逻辑主语，概括起来会有三种情况：不定式作主语、动名词作主语 和 名词从句作主语。
典型的句型如下：
从句作逻辑主语
It is so happened that the tickets were sold out.
It is extremely obvious that she has been lying about her identity.
It suddenly occurred to me that the message must have been hidden between the layers of the briefcase.
不定式作逻辑主语
It is very kind of you to give me a hand in time.
It is my pleasure to address the meeting.
It was pretty hard for him to bring up the child on his own.
动名词短语作逻辑主语
这类句子远不如前面两种出现率高，主要在（no good,waste,useless,no use,dangerous）等词语的后面用
It is no use reasoning with him.
It is no good reading in dim light.
也就是说，如果是在主从复合句中，it做形式主语一般出现在主句部分，后面带that或者of和for等介词。
此处并无此特征，判断为普通代词。
以上~~~
我认为你的分析是正确的，其他问题回答如下：
1.because是从属连词，表示因果关系，可以引导原因状语从句，表语从句和主语从句。
2.it此处是普通代词，指代前文that。
it作为形式主语只是为满足语法上的需要，避免句子头重脚轻，它代替的是句子的逻辑主语，概括起来会有三种情况：不定式作主语、动名词作主语 和 名词从句作主语。
典型的句型如下：
从句作逻辑主语
It is so happened that the tickets were sold out.
It is extremely obvious that she has been lying about her identity.
It suddenly occurred to me that the message must have been hidden between the layers of the briefcase.
不定式作逻辑主语
It is very kind of you to give me a hand in time.
It is my pleasure to address the meeting.
It was pretty hard for him to bring up the child on his own.
动名词短语作逻辑主语
这类句子远不如前面两种出现率高，主要在（no good,waste,useless,no use,dangerous）等词语的后面用
It is no use reasoning with him.
It is no good reading in dim light.
也就是说，如果是在主从复合句中，it做形式主语一般出现在主句部分，后面带that或者of和for等介词。
此处并无此特征，判断为普通代词。
以上~~~
