一般疑问句中do和does的用法好多句子我都不知道前面是Are you...还是 Do you...,

告诉你哈
Are是be动词（系动词）,也就是说它是一个谓语动词,一般用于主系表结构或者是表示什么人是什么（身份）.
当肯定句是以be动词作谓语时该疑问句用Are(am is)开头
例子 I am a student.
Am I a student?此处student是名词,意为我是个学生
或者 It is hard to him to win the campaign.
Is it hand to him to win the campaign?这是It is adj形容词.结构是It is adj to sb.to do sth.此时it作形式主语无实意.is为系动词,形容词作表语.
Do是助动词 不作谓语使用当原句是以实意动词作谓语（譬如：take,eat等等）就要以do开头改疑问句
例子：I want to eat something.
Do you want to eat something?
谓语是eat所以用助动词do开头
明白否?
不明白可以给我发信息.