modal in the past form

Modals in the past are :
1. Could
2. Would
3. Should
4. Shall

*Could + Verb base
We can use this expression : to offer suggestion or possibilities.
Example :
Aditya : I’m having trouble with physics.
Dodi : Why don’t you ask Danar ?
Perhaps she could help you.

*Might + Verb base
Use might to tell possibillities.
Example :
Rizki : Why is Alvin taking the bus to get home.
Fredy : He might get a flat time.

*Would + verb base
Use would for an action that was repeated regulary in the past.
Example :
Danar : What did you usually do on holidays ?
Aditya : I would visit my grandparents In the Surabaya, but how not anymore.

*Would + Mind + V-ing
Use would to express polite request.
Example :
Dodi : Would you mind posting the letter ?
Dwima : No, Not at all.

*Should + Verb base
Example :
Alvin : Fajar ,you should go to library now ?
Fajar : O.k.