For questions and advice

To express questions:

Can, could, will and would are used to express requests:

Eg:Can you lend me $10?

Can I borrow your car?

Could you tell me where the train station is?
Could I have a cigarette?
Will you turn off your mobile phone, please?
Would you open the door for me?
Would you mind stepping outside for a moment?


To express advice:

Should, ought to and had better can express advice:

Eg:You should smoke less.

We‘d better leave soon.
You ought to thank her. 

Ought to is less frequently used and is more formal.