most people think that jazz107.9FM is really great 中的that什么用

这是一个宾语从句, that jazz107。9FM is really great 是think的宾语。以下是宾语从句的语法介绍：宾语从句(The Object Clause)在复合句中作主句的宾语。宾语从句通常由下面一些词引导。1、由that 引导的陈述句性的宾语从句,在很多动词如say, think, wish , hope, see, believe, agree, expect, hear , feel等后。连词that只起连接作用,在从句中不做任何成分,也无词汇意义,在口语中常被省略,但在大多数情况下还是以不省为好。例：I told him that he was wrong。2、 由wh-引导的宾语从句,连接代词who,whom,whose, what, which,和连接副词when, where, why, how 等连接的宾语从句,它们在句中即有连接从句的作用,又在句中充当句子的成分。例：Do you know which film they are talking about? (which做定语)I don’t know where he lives。 (where 做地点状语)3、 由连词whether 或 if 引导（一般情况下两者可替换,口语中常用if）。我们应注意的几个问题：1、 宾语从句的语序。宾语从句的语序必须是陈述语序,既连接词+主语+谓语+其他成分例：I believe that they will come soon。He asked me whether I was a teacher。They wanted to know what they can do for us。2、 宾语从句的时态1）宾语从句的时态受主句的限制,主句用一般现在时,从句也用现在时态。如：He says Mary is playing with the cat 。He says Mary often plays with the cat。2) 主句是一般过去时态,从句用相应的过去的时态。如果从句的动作发生在主句之前,则从句要用过去完成时态。 He said Mary was playing with the cat。He said he hoped to be back soon。。3) 当从句所表示的是客观真理、自然现象或事实时,这时宾语从句都用一般现在时。如：He said light travels much faster than sound。The teacher said that the earth goes round the sun。3、 宾语从句中的否定转移。如果主句谓语动词是think , believe suppose 等,而从句的意思是否定的,这时主句的谓语动词用否定式,从句用肯定式。如：I don’t think you are right。 我认为你不对。4、 将特殊疑问句变成宾语从句时,从句的语序要由疑问句变成陈述句的语序。When will the meeting begin?-------I want to know when the meeting will begin。5、 将一般疑问句变成宾语从句时,则用if /whether连接,同时变成陈述句语序,同时注意人称的变化。Are you an English teacher ?-------He asked if I was an English teacher。注意：由连词if、 whether 引导的表示“是否…”的宾语从句。Whether,if 在从句中不做句子的成分,一般情况下,whether和if 可以替换。但在下列情况下只能用whether,不能用if1） 介词后的宾语从句 I’m thinking about whether we should go fishing。2） 宾语从句提前时 Whether this is true or not, I can’t say。3） 宾语从句中有or not时 I don’t know whether or not he was ready。4） 和动词不定式连用作宾语时 She hasn’t decided whether to go or not。当" if "引导条件状语从句,（主句是将来时,那么从句就用现在时；主句是过去时,从句则用过去完成时）。例　I don’t know whether he will come。 If he comes ,I will tell you。