Поставить глаголы в форме Present Participle и Past Participle.

to see

to feel

to sit

to work

to do

to understand

to discus

to know

to smell

to cry

Present Participle Simple: seeing, feeling, sitting, working, doing, understanding, discussing, knowing, smelling, crying.

Present Participle Perfect: having seen, having felt, having sat, having worked, having done, having understood, having discussed, having known, having smelt, having cried

Past Participle: seen, felt, sat, worked, done, understood, discussed, known, smelt, cried