At Christmas,people____carols toget into the Chirstams ____

但是你是指‘to get’还是‘together’?

如果你是指‘together’的话，
At Christmas, people sing carols together in the church.(Christmas就不用了)

如果你是指‘to get’的话，
At Christmas, people sing carols to get into the Christmas spirit. （个人认为‘spirit’用法在这里更好。）

sing atmosphere
??不确定

sing,party

sing ,church

圣诞节，人们都在教堂唱圣诞颂歌。