I他马克思耨It makes no difference if(whether).

由于这个句子实际上的主语（if/ whether 引导的主语从句）太长,而用it作为句子的形式主语,make是句子的谓语
It makes no difference whether he will attend the meeting or not.他是否会参加会议都无关紧要.
It makes no difference if he doesn't know me.
他知不知道我并没什么区别.
it构成的主语从句
（1）由连词that引导的主语从句,在大多数情况下会放到句子的后面,而用代词it作形式主语.如：
It is well-known that the earth moves around the sun.众所周知,地球围绕太阳转.
需要注意的是,it作形式主语代替主语从句时,要注意和as引导的定语从句的区别.试比较：
It was reported that the US was under the terrorist attack.（主语从句,有that,无逗号）
As was reported,the US was under the terrorist attack.（定语从句,无that,有逗号）上两句意为“据报道,美国遭到*的袭击”.
（2）常见用it作形式主语的复合句结构
It is a fact （a good idea / a pity / a shame / no wonder / good news…）that…如：
It's a pity that you missed the film.你没有看那部电影真是太遗憾了.
It is necessary （clear / true / strange/ important /wonderful / possible / likely…）that…
需要注意的是,这类主语从句中,谓语动词很多为“（should）＋动词原形”,即要用虚拟语气.如：
It is necessary that you （should）master the computer.你很有必要掌握电脑.
It is important that a student learn English well.学生学好英语很重要.
It's clear that they badly need help.很明显,他们急需援助.
It is likely that a hurricane will arrive soon.飓风很可能马上就要到达了.
It is reported （well-known / hoped / thought / expected /said /believed/decided /suggested /ordered…）that…如：
It is said that he was killed in the earthquake.据说他在地震中丧生了.
It seems （happened / appears / doesn't matter / makes no difference / …）that …如：
It seems that they will win the game.看起来他们好像会赢得这场比赛.
It makes no difference whether he will attend the meeting or not.他是否会参加会议都无关紧要.