Knock Knock Trick or treat 歌词(每段唱2遍) Knock. Knock. trick or treat? Who are you? I"m a ghost. I"m a little ghost. Trick or treat? I"m a cowboy. I"m a little cowboy. I"m a witch. I"m a little witch. I"m a monster. I"m a little monster. I"m a ballerina. A little ballerina. I"m a pirate. I"m a little pirate.