single-handed

grammar · medium

易错句子She wrote the whole dictionary by single-handed.

正确表达She wrote the whole dictionary single-handed.

single-handed 本身作形容词/副词，意为“独自地、无人帮助地”，可以直接修饰动词，前面不加介词；这里的 by 是汉语“靠自己”类推出来的（如 by oneself），去掉 by 后句子才合法。

grammar · medium

易错句子He repaired the roof single hand.

正确表达He repaired the roof single-handed.

single-handed 是带 -ed 后缀的形容词/副词，不能拆成名词短语 single hand；汉语“单手”逐字直译会丢掉词尾，使句子缺少合法的状语形式。

grammar · medium

易错句子He is still single-handed, so he cooks for himself every day.

正确表达He is still single, so he cooks for himself every day.

single-handed 只表示“独自完成、无人帮助的”，不表示“未婚、单身的”；汉语“单身”对应 single，不能按字面把它套到 single-handed 上。