past tense verbs

For most verbs,we add ________ to form the simple past tense past tense,present tense,past participle simple past&past continue tense The past tense of past tense是什么意思 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