we think that is necessary还是we think that it is necessary

其实从语法上来说,两个都是行的,不过运用到的知识点不一样而已1.we think that is necessary 我们认为那是有需要的.主语 we 谓语 think 宾语从句 that is necessary.that在从句中充当主语,是一个代词,代指“那个,那...I could't understand【 what 】was the matter with me.还是…what the matter was with me这里 I couldn't understand后面what引导一个宾语从句，宾语从句后面的语序是陈述的，而遇到the matter 时，比较特殊，有两种情况。1. 语序是 what was the matter 时，意思是“有什么问题”， 主语是what, 宾语是was2. 语序是 what the matter was时，意思是“这物质是什么”，主语是the matter“这物质”， 谓语是was而这里有个with me,根据句意，是“我出什么问题了”，所以是 I couldn't understand what was the matter with me. /I couldn't understand what was wrong with me.