有一个室友的好处之一就是你可以和他分摊房租（share,表语从句）令我失望的是他太粗心了以至于不能通过考试（so ...as to,表从）

One of the benefits to have a roommate is that you can share the rent with him (her).What made me disappointed was that he was so careless as to fail to pass the examination.