should we attempt language based question (like S.I, C.I, time and work e.t.c) in quantitative aptitude in exam or not?

i would suggest no,, better go for data interpretation question it will fetch u 10 marks in one go,, then go for quadratic or simplification or series type depending upon which ever is comfortable for you

It is safe to be prepared for all types of questions because sometimes questions from si and ci might be easier to solve(< 40secs) compared to others.
You should decide on whether to attempt or skip a question depending on how difficult it is, but never ever skip any topic while preparing.