英语中9个基础情态动词常令学习者困惑：
can, could, may, might, must, shall, should, will, would
它们具备以下共性：
- 形式固定：无第三人称单数变化（无-s）、无过去分词（无-ed）、无现在分词（无-ing）
- 正确：She can swim. / 错误：She cans swim.
- 搭配动词原形：直接接动作动词，不加to
- 例：I might go shopping.
- 独立使用：避免重复时可单独出现
- 例：”Will you come?” “I might.”
- 疑问句倒装：无需助动词do/did
- 例：Can you help me?
- 否定加not：常缩写（如can’t, won’t），但may not不缩写
9大情态动词用法精解
1. Can
- 能力：I can speak French.
- 请求/许可：Can I open the window?（日常）
- 可能性：London can be rainy in spring.
- 否定推断：She can’t be home（门锁着）
2. Could
- 过去能力：I could run fast as a child.
- 委婉请求：Could you pass the salt?（更礼貌）
- 可能性推测：The keys could be in the drawer.
3. May
- 正式请求/许可：May I leave early?（正式场合）
- 可能性（50%）：The meeting may be delayed.
4. Might
- 较低可能性（30%）：It might rain later.
- 过去推测：He might have forgotten（无证据）
5. Must
- 肯定推断（90%）：You must be tired（脸色苍白）
- 强制义务：You must wear a seatbelt.
- 禁止：You mustn’t smoke here.
6. Shall
- 建议/提议（英式常用）：Shall we order pizza?
- 未来计划：I shall call you tomorrow.（正式）
7. Should
- 建议/义务：You should drink more water.
- 预期结果：The train should arrive on time.
8. Will
- 未来肯定：I’ll visit Shanghai next month.
- 承诺：I won’t tell anyone.
- 直接请求：Will you turn off the light?
9. Would
- 虚拟假设：If I were rich, I would travel.
- 委婉请求：Would you mind waiting?
- 过去习惯：He would jog every morning.
随堂小测验
Q1：When I was young, I _ climb trees easily.
答案：could（过去能力）
Q2：The lights are off—they _ be asleep.
答案：must（高概率推断）
Q3：_ I use your phone? Mine is dead.
答案：Could/May（礼貌请求）