Hello! I see your confusion! Ask any native speaker and they will find it hard to explain the difference as there are really similar.
All 4 words you mentioned means "BUT". So what are the difference? Let's take a close look.
可是 - usually it's used in oral conversation.
但是 - can be used in conversation and writing.
只是 - besides "but", it is often used as "barely". For example : 這只是一件小事。This is only a small matter.
不过 - besides "but", it is often used as "barely" as well and it's more formal than 只是. For example: 他不过是一个孩子。 He is only a child.
Yet, if your sentence is something like...我想去吃火锅，........我钱不够了。"I want to go to hot pot, but I don't have enough money." Then you can park in 可是，但是，只是 or 不过。Really not mcuh difference. I might say if you use the later two, you might sound that you have a wider range of vocalbulary but the result of what you try to get through are the same.
So to sum up, all four words share the meaning of "but", however, 可是 and 但是 you can consider them as a more similiar pair; 只是 and 不过 as another pair which has extra meanings as "barely".
Hope this helps!
Ying Ying
(more)All 4 words you mentioned means "BUT". So what are the difference? Let's take a close look.
可是 - usually it's used in oral conversation.
但是 - can be used in conversation and writing.
只是 - besides "but", it is often used as "barely". For example : 這只是一件小事。This is only a small matter.
不过 - besides "but", it is often used as "barely" as well and it's more formal than 只是. For example: 他不过是一个孩子。 He is only a child.
Yet, if your sentence is something like...我想去吃火锅，........我钱不够了。"I want to go to hot pot, but I don't have enough money." Then you can park in 可是，但是，只是 or 不过。Really not mcuh difference. I might say if you use the later two, you might sound that you have a wider range of vocalbulary but the result of what you try to get through are the same.
So to sum up, all four words share the meaning of "but", however, 可是 and 但是 you can consider them as a more similiar pair; 只是 and 不过 as another pair which has extra meanings as "barely".
Hope this helps!
Ying Ying