以前瘦小用英语怎么说呢

"瘦小"用英文可以表示为"slim"或"thin"。这两个词的意思都是瘦，但是"slim"通常指的是身材纤细，体态苗条，而"thin"则指的是身体瘦弱或肌肉稀少。

来源：

"Slim"来自中世纪拉丁文"exslimare"，意思是削减、减轻。
"Thin"来自古英文"þynne"，意思是稀薄、轻薄。

一些例句及翻译：

She's always been slim, but now she looks even slimmer. (她一直很瘦，但现在看起来更瘦了。)
He used to be quite thin, but he's put on a lot of weight recently. (他以前很瘦，但最近体重增加了很多。)
She's always been thin, but now she looks too thin. (她一直很瘦，但现在看起来太瘦了。)
He's always been slim, but now he looks too thin. (他一直很瘦，但现在看起来太瘦了。)