That is why,This is why,It is why的区别

that is why和 this is why用法的区别 That is why,This is why,It is why的区别 So why is that why is that? Maybe this is the reason that why love is beautiful.应该去掉that还是去掉why,为什么, Why is this crazy?还是 why this is crazy? You say this is why? why?why?why?why?this is a question. I don't know,what's the situation.What is this?Why is that Is there anyone can tell me that this sentence:Why i matter?is wright or wrong That is why I took that is why是什么从句 关于that.is.why.,句型 Is that this watch? This is the reason ——I came hereA.that B.why 为什么不用that 有that'S why 这个句型吗..不是the reason why is that /it's because that this is because that that is why number13 is unlucky This is mine friend or This is my friend why?