am -was need-needed line -lined follow -followed learn -learned open -opened look -looked like -liked sing -sang call -called dance -danced use-used 改动词原形中的aw /ow为ew,变成过去式.如...
am -was need-needed line -lined follow -followed learn -learned open -opened look -looked like -liked sing -sang call -called dance -danced use-used 改动词原形中的aw /ow为ew,变成过去式.如...