英语逻辑推理.求解答Mr Smith was killed at home last night!And a lot o

英语逻辑推理.求解答
Mr Smith was killed at home last night!And a lot of gold coins were missing!Sherlock Holmes found a silver earring in Mr Smith's hand!Who killed him?Who does the earring belong to?
In fact,there were two servants in the house at that time,a girl called Sally and a boy called Tom.Sally was 26 years old.She was going to marry the next year.She liked to wear earrings.So it might be hers.
Tom was 20 years old.He had a girlfriend in the country.He had little money because he spent most of the money drinking in the pub.It could also be his,as a gift for his girlfriend.After Holmes looked at the earring carefully,he took Tom away.He said,"It must be Tom's."What he said was true.
史密斯先生昨夜在家中被杀!大量金币丢失!夏洛克福尔摩斯在史密斯先生手中找到了一个耳环!谁杀了他?这个耳环是谁的?
　　事实上,当时房中有两个仆人：姑娘莎莉和小伙子汤姆.莎莉26岁,准备明年结婚.她喜欢戴耳环,所以这可能是她的.
　　汤姆20岁,有个女友在乡下.他几乎没有钱,因为他把钱几乎都花在在酒吧里喝酒了.这也可能是他的,是他买给女友的礼物.福尔摩斯仔细看了看耳环,带走了汤姆.他说：“这肯定是汤姆的.”他说的是真的.
那位高手能想出来么?在线等