The key answer of exercise 1
The key to exercise solutions in chapter Workbook - You live and learn for the textbook Performer B1 Phases, Vol. 1 with authors M. Spiazzi, M. Tavella, M. Layton, E. Fiordiliso from Zanichelli
Question
Revise the grammar reference and complete the grammar map.
Answer
MUST
FORM
It is a modal verb, so it is invariable and always followed by the base form of the main verb.
It is used only in the present simple form. In all other tenses it is substituted by have to
USE
To talk about a strong personal obligation or necessity.
Example:
- I must learn German; I think it's important.
To give direct orders (orally or in written instructions and formal notices).
Example:
- You must finish your homework before dinner.
Students must wear school uniforms at all times.
To express strong recommendation.
Example:
- You must see the doctor: you look very sick
HAVE TO
It isn't a modal verb, so it follows the rules of the verb have.
USE
To talk about an external obligation (imposed by laws, regulations, other people).
Example:
- In most primary schools, children have to wear a uniform.
To report other people's orders or instructions.
Example:
- My boss said I have to submit the report by Friday.