SUM
sum, esse, fu-i, fut-urus - be, exist
absum, abesse, afu-i, afut-urus - be away, absent, distant
adsum, adesse, adfu-i, adfut-urus - be present
desum, deesse, defu-i, defut-urus - fail, fall short, lack
insum, inesse, infu-i - be in / on, belong to
intersum, interesse, interfu-i, interfut-urus - be amongst, be present at, (time) elapse
obsum, obesse, offu-i, offut-urus - be against, hinder, injure
praesum, praeesse, praefu-i - be in front, be in charge
prosum, prodesse, profu-i, profut-urus - be useful, benefit, profit
subsum, subesse - be under, be at hand, be latent in
supersum, superesse, superfu-i, superfut-urus - be left over, survive, abound

POSSUM
possum, posse, potu-i - be able, can