By heart 表示记得非常熟，能逐字重复。最常见的搭配是 learn something by heart 和 know something by heart，内容可以是诗、电话号码、歌词或戏剧台词。
想在对话中用 by heart 吗？
写一句英语，查看错误和更自然的表达建议。
本次检查比平时稍久，完成后反馈会自动显示在这里。
learn + something + by heart; know + something + by heart; from memory (= without looking)
- As a child, I had to learn a long poem by heart for the school concert.
- I still know my grandmother's old phone number by heart.
- Don't just learn useful phrases by heart; practise building sentences with them.
修改原因
修改前I know my passport number by memory.
修改后I know my passport number by heart.
By memory 看起来合理，但不是这里的自然英语搭配。要说某件事已经记熟，用 by heart，常与 learn 和 know 搭配。
From memory 表示不看笔记或图片，凭记忆完成：She drew the map from memory。By heart 则强调文字或数字已准确记住：I know the poem by heart。书面语中，memorise 常可替代 learn by heart，例如 memorise key dates。
动手练习
We've sung this song at every family party, so I know all the words ___.
查看答案
by heart — 这首歌唱过很多次，歌词已经准确记住，所以选 by heart。By memory 不能在这里代替这个常用表达。
想一个你能背出来的内容，例如诗、歌或号码。使用 by heart，说明是什么，以及为什么记住了它。
I know a short Pushkin poem by heart because we had to learn it at school.
练习把新词用准确
用正在学的词造句。LetsWords 检查用法和语法，提供修改与母语解释，再通过复习巩固。