Modal 情绪 和 态度 ，+  动词原形

must 必须       mustn’t 禁止

• We must finish the homework within a week.
• Air pollution must be taken seriously.

can/could  “能够，可以”

• The government can solve the problem of water pollution.
• Tom could walk when he was only one year old.

will/would “愿意/将要”

• Will you marry me?
• I will travel abroad with my family.

may/might  “可以,可能”

• To some extent, expressions may influence emotions.
• Such bodily reaction might help moderate the work stress.

Should “应该”

• Students should work hard to pass the exams.
• Those sick people should seek help from doctors.

• The details may be unknowable.
• Such searches must take years.