what r the reasons for a database to go to suspect mode in sybase and what r the steps to recover it

Looks like an interview question to me. Have you faced a suspect problem? If so, please give details. If you are just curious, then the core reasons for a db to be marked suspect is

a) when for some reason, it doesnt have access to the devices it was originally created on.
b) theres some corruption in the database.

The suspect situation is not something you plan/prepare for, and thats why they termed it "suspect" and basically you react to the situation based on the errors ASE is showing you.

So, the way to recovery totally depends on how it got into suspect mode.