求教英语语法,although,which is the reason,balabalabala.那个逗号怎么用?

求教英语语法,although,which is the reason,balabalabala.那个逗号怎么用?
我想说的是（英语的思维）：尽管我所学的东西和实际工作有很大的差距，（这是我所申请的第二个原因），但是我做了很多别的来说试图shorten它。
Although there is a distance between what I have learnt and the practical work,which is the second reason of applying for a intern,省略N个字。我想问：which前加了逗号对不对，我想修饰前面的整句话；去掉了逗号，是不是就还成了修饰 the practical work。
或者我整句话都错了，压根就没这用法，帮重写个也行。总之要用到second reason，要从句，要长！