past tense是什么意思

past tense是什么意思 past tense,present tense,past participle simple past&past continue tense The past tense of Simple past tense past perfect tense Past Simple Tense present perfect tense,past perfect tense Simple present tense转换Simple past tense 用present perfect tense ,simple past tense , past tense和past continue tense怎样区别啊 Past tense的意思.拜托!