英语知识帮助,though与although的区别?

题目

英语知识帮助,though与although的区别?
Second,__the self-employed can earn considerable profits with a successful business ,losses can force them out of business,and in some instances ,place them in debt.
这是一个完形填空里的一处空格.横线处为什么要用though而不用although?
（另外in some instances是什么意思啊?）

答案

although和though作连词时意思相同“虽然”,不同之处是though可作副词,although不能.
in some instances的意思是“在某些实例中”.全句意思：
其次,虽然个体经营者在生意成功的情况下可以赚取可观的利润,但是生意失败可把他们逐出此行,在某些实例中,还让他们负债.