连词成句：have,no ,I ,a ,but ,sister ,brother (.)

I have no sister but a brother或者
I have no brother but a sister都可以。

I have a sister but no brother

应该是：I have a sister but no brother.

I have no brother but a sister .
或者 I have no sister but a brother.

意思是“我没有兄弟，只有个姐姐” 我没有姐妹，只有个哥哥“

I have a sister but no brother.

I have no brother but a sister
意思是我没有兄弟但有姐妹
(brother和sister可以换一下,意思是我没有姐妹但有兄弟)