姐姐和妹妹在英语中分别读作 "sister" 和 "younger sister".
"Sister" 来源于古英语 "sustre",意思是 "女性兄弟姐妹",在中世纪英语中还有 "sister-in-law" 的意思,指的是姐妹或兄妹的配偶。
"Younger sister" 来源于英语 "young",意思是 "年轻的",和 "sister" 结合,就是 "年轻的姐妹"。
例句:
I have an older sister and a younger sister. (我有一个姐姐和一个妹妹。)
My sister is two years older than me. (我的姐姐比我大两岁。)
My younger sister is very talented in music. (我的妹妹非常有音乐天赋。)