about job vacancy

salam.. last saturday i had read 'The Star'. part 'job star'.. i found that there are so many advertisement about jobs. from my point of view to some of the advertisement, much information that we can get from there. companies stated all requirement they need that related to the job offered. besides that, mostly big companies stated what type of responsibility according to job offered such as engineers, supervisors, executive. but some companies only stated types of requirement. no responsibility stated in their vacancy such as administration, accountant, marketing and sakes manager. maybe it is because they think that this work field was a common knowledge to all people. the tasks and responsibilities are mostly similar among all companies.