modal verbs表达能力、可能性、许可、建议、义务和礼貌请求。比较"I go"、"I can go," "I should go,"和"I must go."，动作相同，含义不同。基础知识请参阅英语语法完整指南。
基本结构
主要形式有"can," "could," "may," "might," "must," "shall," "should," "will,"和"would"。
subject + modal verb + base verb
"She cans speak English."错误；"She can speak English."正确。"We must to leave."错误；"We must leave."正确。疑问句可说"Can you help me?"，否定句可说"You should not worry."
主要含义
"Can"表示现在的能力；"could"表示过去能力、礼貌请求或可能性："Could you repeat that, please?"。"May"和"might"表示可能性："She may join the class tomorrow."。
"Should"表示建议："You should practice speaking every day."。"Must"表示强制义务或判断："You must show identification."；"She must be tired."。
"You must not enter"表示禁止，"You do not have to enter"表示没有必要。"Would"用于请求、假设和偏好："Would you help me?"和"I would like a cup of coffee."。这些表达也有助于商务沟通。
在Columbia West College (CWC)，学生会在真实交流中练习这些区别。English Speaking Success (ESS)每天提供80分钟Speaking class，练习量是普通listening and speaking class的6倍。
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常见错误与练习
- 错误："I must to study." 正确："I must study."
- 错误："She can speaks English." 正确："She can speak English."
- 错误："I will can attend." 正确："I will be able to attend."
填写："You ___ review your notes."（建议）、"She ___ speak three languages."（能力）、"It ___ rain."（可能性）。答案是"should," "can,"和"might/may."。可配合English Speaking Practice朗读练习。
真实对话
CWC整合Grammar、Speaking和Reading & Writing。"Connection Questions"鼓励自然使用target English，每周presentation培养专业表达信心。继续使用English Conversation Practice增加重复练习。
疑问句与否定句
疑问句不使用"do"："Can you help me?" 否定句把"not"放在modal后："You should not worry."和"They might not agree."
Can与Could
"I can understand the lesson."表示现在能力；"When I was younger, I could run fast."表示过去能力；"Could you repeat that, please?"是礼貌请求。
May与Might
"She may join the class tomorrow."和"The answer might be correct."表示可能性。"He may have missed the train."表示过去可能性。
Should
"You should practice speaking every day."表示建议。"I should have studied earlier."表示过去未采取的建议。
Must与Have To
"You must show identification."表示强制义务。"I have to attend the meeting."表示实际需要，"He had to leave early."表示过去义务。
Will与Would
"I will call you tonight."表示未来决定。"Would you help me?"是礼貌请求，"I would like a cup of coffee."是礼貌偏好。
Shall与类似表达
"Shall we begin?"提出建议。"She was able to attend."和"We will have to wait."可以表达不同tense。
根据含义与Tone选择
比较"Open the window.", "Can you open the window?", "Could you open the window?"和"Would you mind opening the window?"，后面的形式更间接、礼貌。
FAQ
Modal verbs要加"-s"吗？
不要。应说"She can speak."，不是"She cans speak."。
"Should"和"must"有何区别？
"Should"表示建议或预期；"must"表示强烈义务或确定判断。
modal verbs让表达更准确、礼貌、自信。CWC把Grammar与每日Speaking practice相结合。若想在Los Angeles学习英语，请联系Columbia West College。
