不能同时出现在一个句子中的连词

1、because（因为），so（所以）不能同时出现在一个句子里，只能用其一。

Because he was tired， he couldn’t walk there.

=He was tired ，so he couldn’t walk there.

因为他累了，所以他不能走到那儿了。

2、（al）thouthg(虽然)，but (但是)不能同时出现在一个句子里，只能用其一。但thouthg和yet可以同时出现在一个句子里（yet用作副词）

Thought he was tired， he still worked hard.

=He was tired， but he still worked hard.

虽然他很累，但他仍然努力工作。