动词变成过去式有哪些规则?

1．把动词原形中的i改为a,变成过去式.如：begin—began,drink—drank,give—gave,ring—rang,sing—sang,sit—sat,swim—swam 2．把重读开音节中的i改为o,变成过去式.如：drive—drove,ride—rode,write—wrote 3．...