YOU SAID:
i am going to a party at christmas
INTO JAPANESE
私はクリスマスにパーティーに行きます
BACK INTO ENGLISH
I will go to the party on Christmas
INTO JAPANESE
私はクリスマスのパーティーに行きます
BACK INTO ENGLISH
I will go to the Christmas party
INTO JAPANESE
私はクリスマスパーティーに行きます
BACK INTO ENGLISH
I will go to the Christmas party
You've done this before, haven't you.