"it"做形式宾语的用法

谁能帮我总结一下宾语从句的用法呀？

宾语从句：是做动词、介词或形容词宾语的从句。 一、做动词的宾语： I think (that) you will like the pictures。 我想你会喜欢这些画的。 （连接词that无意义，在从句中不充当任何成分，可以省略） 当宾语从句（通常是由that引导的宾语从句）有一宾语补足语时，常用it作形式宾语，而将宾语从句置于句末。例如： I feel it important that they finish their own task in time。 （我觉得他们按时完成自己的任务是很重要的。） 二、做介词宾语： They are worrying about wh...全部

   宾语从句：是做动词、介词或形容词宾语的从句。 一、做动词的宾语： I think (that) you will like the pictures。 我想你会喜欢这些画的。
   （连接词that无意义，在从句中不充当任何成分，可以省略） 当宾语从句（通常是由that引导的宾语从句）有一宾语补足语时，常用it作形式宾语，而将宾语从句置于句末。例如： I feel it important that they finish their own task in time。
   （我觉得他们按时完成自己的任务是很重要的。） 二、做介词宾语： They are worrying about whether they can get there in time。
   You can write about whatever topic you can think of。 三、做形容词宾语： Are you sure what you will do next? I'm afraid that he will fail in the exam。
   表语从句 表语从句：表语从句置于连系动词后面做表语。例如： The question is whether the book is worth reading at all。
  （问题是这本书是否有点读的价值。） That is why we don't like it。 It seems that all of the students have done their homework。
   My idea is that we should all do our best。 This is where we found the strange trees。 It seems that everybody agrees to the decision。
   同位从句 　 同位从句一般跟在某些名词如answer(答案)，hope(希望)，fact(事实)，belief (信仰)，news(消息)，idea(主意；观念)，promise(承诺)，information(信息)，conclusion(结论)，order(命令)， suggestion(建议)，problem(问题)，thought (想法)等后面。
  例如： 　 He always works hard even if he knows the fact that he is 　 not in good health。 　 His failure was due to the fact that he had not practised 　 for a long time。
   　 I had no idea that you were here。 　 She told us her hope that she would become a pianist。
   　 He made a promise that he would never come late。 注意： 　 that 既可引导同位语从句又可引导定语从句，其区别在于：同位语从句由连接词that引导，连接词that本身无意义，在同位语从句中不充当任何成分，不可省略，不可以用其他词替代；定语从句由关系代词that引导，关系代词that在从句中充当一定的成分，作宾语时可省略，由when, why, where引导的 同位语从句和定语从句的区别在于： 　 同位语从句由连接副词只起连接作用，没有指代作用； 定语从句由关系副词引导，关系副词具有指代先行词的作用，常用一个介词加关系代词替换。
   例如:I will never forget the day when we first met。 （同位语从句, when为连接词） That is the special day (which/that) I will never forget。
   （定语从句，which/that为关系副词） This is the house where we lived fifteen years ago。 （同位语从句, where为连接词） This is the house which we sold fifteen years ago。
   （定语从句，where为关系副词） 。收起