语法点：used to / would / be used to (Past Habits)
used to + 动词原形表示过去经常做、现在已经不做的事，或者过去存在、现在不存在的状态（used to live）。would + 动词原形也能表示过去反复发生的动作，但只能用于动作，不能用于状态（不能说 would live），而且通常需要上下文先交代时间背景。be used to + 名词 / -ing 意思完全不同："习惯于"，这里的 used 是形容词，to 是介词，所以后面接名词或动名词，可以用于现在、过去或将来。本课作者回忆小时候常坐飞机（used to travel），乘务员总会照顾他（would take charge），所以现在已经习惯了坐飞机（am used to travelling）。
结构
| 结构 | 意义 | 例子 |
|---|---|---|
| used to + 动词原形 | 过去常常 / 过去曾经（现在不再） | I used to travel by air. |
| did not use to + 动词原形 | 否定 | I did not use to fly. |
| Did + 主语 + use to …? | 疑问 | Did you use to live there? |
| would + 动词原形 | 过去反复的动作（不用于状态） | A flight attendant would take charge of me. |
| be used to + 名词 / -ing | 习惯于（现在的状态） | I am used to travelling by air. |
| get used to + 名词 / -ing | 逐渐习惯 | I got used to flying alone. |
课文中的例句
- [句 1] I used to travel by air a great deal when I was a boy. — used to + 动词原形，过去常常坐飞机，现在不再
- [句 2] My parents used to live in South America and I used to fly there from Europe in the holidays. — used to 既可以接状态动词 live，也可以接动作动词 fly
- [句 3] A flight attendant would take charge of me and I never had an unpleasant experience. — would + 动词原形表示过去反复的动作，前面已有时间背景
- [句 4] I am used to travelling by air and only on one occasion have I ever felt frightened. — be used to + -ing 表示现在已经习惯
补充例句
- My father used to smoke, but he gave it up last year. — 我父亲过去抽烟，但去年戒了。
- When I was a boy, my mother would read to me every night. — 我小时候，母亲每晚都会读书给我听。
- She is used to getting up early. — 她习惯早起。
易错点
- ❌ I used to travelling by air when I was a boy. → ✅ I used to travel by air when I was a boy. — used to 后接动词原形，表示过去习惯。
- ❌ I am used to travel by air. → ✅ I am used to travelling by air. — be used to 里的 to 是介词，后接 -ing。
- ❌ My parents would live in South America. → ✅ My parents used to live in South America. — would 不能用于 live 这类状态动词。
- ❌ I use to fly there in the holidays. → ✅ I used to fly there in the holidays. — 表示过去习惯必须用 used to，不能用 use to。