I'm sorry后为什么要接but

I'm sorry后为什么要接but 为什么I'm sorry,but是固定词组 i'm so sorry but i love BE动词后可不可以加to 比如I'm to sorry but i love You i'm sorry.but l love you. I'm sorry,_____I won't be able to come tonight.为什么设空处填but“表转 是I'm sorry I can't 还是I'm sorry but I can't I'm sorry,I love you but I can I'm so sorry but I love you都是谎言. Sorry I'm wrong,but I am still loving you. I'm terribly sorry,but may I use your phone? i \' m so sorry but i love you?