圣诞将至时，办公室玩起了“神秘圣诞老人”的游戏。谁是那个一直悄悄给你送礼物的人呢？

1, Cover for me 代班

2, Run around like a chicken with its head cut off 忙的像无头苍蝇

3, The jig is up 把戏被拆穿了

4, Guilty as charged 认罪