ming bai 明白：it's meaning is understand，意思是明白了，理解了; hui & dong 会懂：：it's meaning is "will understan". 是两个字组合起来的，通常意思下不是一个词语，意思是会理解，会知道；dan shi 但是：means however,but, 表示转折的意思。ke shi 可是：almost the same meaning with the former.也是表示转折的意思。

ming bai and dong have same meaning, means "i see,i understand i know". hui means"i can".in another word, when you understand what someone said or his idea,you can say "wo dong le "or"wo ming bai le", but when you know how to do what someone did or you can do that,you can say "wo hui le".the formers have their meaning in mind,the latter have its meaning in act. about dan shi and ke shi, the latter have a voice gentle.

哈哈，但是和可是almost same for me..谢谢你们的explanation.. 我还一定学汉语很多。。

明白&懂=understand or know；会=can；但是=but；可是=however