Answer:
Liza: May I have a look at it? (Permission)
David: I can't think who it’s from. (Negative ability)
Liza: It might be important. (Assumption)
David: Can you read the postmark? (Ability)
Liza: It could be from your bank manager (possibility), so you should open it immediately. (Advice)
Step-by-step explanation:
Modal verbs are a type of auxiliary (helping) verb used to indicate modality, meaning they are used to show likelihood, obligation, ability, suggestions, order, capability or advice.
As shown above:
- Liza used the verb 'may' is used to ask David's permission to read the letter
- David used 'can't' to express his negative ability to guess who the letter was from
- Liza used 'might' in assuming the letter's importance
- David used 'can' to ask Liza her ability of reading the postmark
- Liza used 'could' to express the possibility of who the sender was, and used 'should' in advising David to open it.