but和however的区别，以下例子中为什么用but?

Question

Karmen may not grow up to be a ballerina, but, despite her difficulty walking, she was transformed when she donned a tutu that her mother had bought her。
看过回答了,我举的例子里面用的是but,可是前后都用逗号隔开了，为什么?

Answer 1

but 和however 都表示转折，但是，然而。最明显的区别就是however 是单独使用的，文中出现在一句话的结尾，一段话的开始，有逗号隔开。
比较：He used to be a good driver, however,he had a traffic accident yesterday.
He used to be a good driver，but he had a traffic accident yesterday.
He used to be a good driver but he had a traffic accident yesterday.
另外but 还表示除.....之外，常用结构have no choice but to do除了....之外别无选择
but 还可以直接接副词。But now, I have no choice but to forget out of my willingness.
可如今，我只能逞强自己选择遗忘。而however不可以。
however除了表示转折以外，还可接其他词，如however much/many/far/often/long等，此时表示无论多...可以相应换成no matter how +much/many/far/often/long
比较People are going to take however much you're willing to give.人永远不会嫌自己拿得多。
In my opinion, parents do not owe their children an inheritance, no matter how much money they have.以我个人的观点，家长们不欠儿女们一份遗产，不论他们多么有钱。
如果还有其他的问题的话，可以去小马过河问问那里专业的英语老师，希望能够帮助到你，谢谢！

Answer 2

向上一位朋友说的 but不能用在开头单独成句 但是however可以 此处but和however都可以 但是用however后面一定要加逗号，but则不用

Answer 3

but 不能在句子的开头用，however可以。