At Christmas Eve, Jim went with his father to choose a Christmas tree. They

On（在圣诞之夜用介词on）

choose a big one. It was almost as taller as the room! They put them in the corner

chose (本文是过去时)   tall（as…as之间用原级）         it （指代前面的圣诞树）

of the sitting room. Kate was covered it with a lot of Christmas light. The sitting

\ （这里用主动语态）                   lights（这里是复数形式）

room looked really beautifully at the moment. There was a fire burn in the fire

beautiful（look后面接形容词作表语）         burning（fire与burn构成主动关系）

place, and the Christmas tree lights were shinning brightly. Jim or his parents

and（这里表示并列关系）

∕﹨singing and dancing happily.

Were(这里使用过去进行时)

如上