第1个回答 2009-05-30
swim--swims--swam-swum
find--finds--found--found
begin--begins-began--begun
play--plays--played--played
study--studies--studied--studied
is/am--is--was/was--was/was
fly--flies--flew-flown
plant--plants--planted--planted
are--are--were--were
drink--drinks--drank-drunk