不能连用。
区别：
though是从属连词，引导从句；
but是并列连词，并列连词可以连接两个独立的主句。
Though：
读音：[ðəʊ]
释义：可是，但是，做副词；但是，做介词。
造句：
（1）、尽管；虽然
Gaelic has been a dying language for many years, though children are nowadays taught it in school...
盖尔语多年来一直濒于消亡，尽管如今孩子们还在学校学习这门语言。
（2）、不过；可是；然而
I look back on it as the bloodiest (though not literally) winter of the war...
我现在回想起来，觉得那是战时最血腥的(但并非字面意义上的)一个冬天。
though事连词,引导让步状语从句,意思是
"虽然……但是”；在句子中如果用了though,就不
能再用but,但可以用yet或still.或者用了but,就不能用though,这一点和用了because不能so，用了so,就不能再用because的用法事是一样的。
例如:
Though the work is hard, I enjoy it.
He thinks I'm too easy-going, but it doesn't matter.
Though we have made some progress, yet we still have a long way to go.
