l) but 但是：
He tried hard but he was unsuccessful.
she 's American but she lives in England.
2) yet 但是：
she has her weaknesses, yet she is honest.
The car was old, yet it was in good condition.
3) however 但是，可是：
He said that it was so, he was mistaken, however.
Most people, however, praised silas.
l) for 因为：
You'd better put on your sweater, for it's rather cold outside.
It must be snowing, for it is so bright outside.
2) so 因此：
My sister is expecting me, so I must be off now.
It was already rather late, so we decided to go home.
3) therefore 所以，为此：
You are in the right, therefore we should support you.
He broke the rules of the school, therefore he had to leave.
4) hence 所以，因而(多用于说理文中):
The word is an uncountable noun and isued in a general sence, hence it takes no artide.