Question

write the past forms of the verbs.
swim _________
skate ________
have _________
is ________
skip _______
see _________
ski _________
see __________
ski _________
are _________
jump _______
go _______
travel ________
rain________

Answer 1

swim-swam
skate-skated
have-had
is-was
skip-skipped
see-saw
ski-skied
are-were
jump-jumped
go-went
travel-traveled
rain- вот тут уже я точно не знаю, либо Was raining, либо rained.
Но второе нигде и никогда,практически, я не слышала и не употребляла, а первое- не Past simple, а Past Continious. 

Answer 2

swim-swam skate-skated have-had is-was skip-skapt see-saw ski-? are-were jump-jumped go-went travel-traveled rain-rained