上周六，你和姐姐逛商店，看见一位外国人想买一件T恤衫，他不懂汉语，售货员也听不懂英语，你上前帮忙，为他们翻译，帮他买到了合适的T恤衫。这位外国人很高兴并向你致谢，姐姐表扬了你。

请你根据以上情景及内容要点提示写一篇文章，词数不少于60。

1、Last Saturday．I went to buy something with my sister．At the shop，I met a foreigner．He is an American．He wants to buy a T-shit．He doesn't know Chinese．And the salesgirl doesn't know English．So I came up to them．I told the salesgirl what the foreigner want to buy in Chinese，then I told the foreigner the price in English．At last，he bought a T-shirt happily．The foreigner thanked me very much．My sister praised me．I'm proud of myself ．

How happy I am!