Here are some common types of functions questions :
(1) Functions + Change
e.g Is X still relevant ?
e.g. Since we have X, do we still need Y ?
(2) Functions + Comparison
e.g. The main/sole purpose of X is __________. Do you agree ?
e.g. Is X merely/simply for _________ ? / X is nothing more than __________. Do you agree ?
(3) Functions + Pros & Cons
e.g. Should X be done ?
e.g. Should X be done when this condition is present ?
e.g. Discuss the value & appeal of X
Check out this slideshow for sample questions :