1. Explain the difference:

-"Must" means must, should, and emphasize the inevitability based on rules, obligations, orders or logic.

-"Need" means need, emphasizing meeting certain requirements or achieving certain goals.

Example:

You must abide by the rules of the organization. )

I need to buy some groceries for dinner tonight. )

2. Differences in usage:

-"Must" is usually used to express mandatory rules, obligations or instructions, and sometimes it also means definite inferences or conclusions.

-"Need" is usually used to express the need or requirement for something or an action.

Example:

Students in this school must wear school uniforms. )

I need some help with this project. )

3. Use environmental differences:

-"Must" is often used in formal occasions, such as laws, rules and regulations, ethics, etc.

-"Need" is more common in daily spoken language and informal occasions, and is used to express actual needs or wishes.

Example:

Employees must attend the meeting on time. )

I need to have a rest. I've been working all day. I need a rest. I've been working all day. )

4. Image difference:

-"Must" gives people a sense of compulsion and irresistible, implying urgency and inevitable necessity.

-"Need" is more focused on meeting needs or achieving a certain goal, which is relatively mild.

Example:

You must finish your homework before you go out to play. )

I need some fresh air after staying indoors all day. )

5. Difference of influence scope:

-"Must" involves mandatory provisions, logical reasoning or moral standards, and has a universal scope of application.

-"Need" pays more attention to individual needs, desires or requirements in specific situations.

Example:

Students must respect their teachers. )

She needs a bath after exercise. )