（1）is→was
(2) go--went
(3) goes--went
(4) fly--flew
(5) saw--see
(6)Tom didn't watch TV last night or Tom wasn't watching TV last night
(7)didn't---didn't do
(8)wait---waited
(9)find--found
(10)have---had
(11)is---was
(12)planed---planed to do
(13)went---go
(14)didn't ---didn't do