present perfect;：indefinite past有一本英语语法书现在这个单元是 present perfect：indefinite past 请问这是什么语法?我想知道这个单元要讲的是什么意思 因为已经讲过present perfect了,为什么还要加一个i

present perfect present perfect simple and present perfect continuous Present simple,present continuous,present perfect simple,present perfect continuous present perfect continous是什么 present perfect是什么意思 The present perfect tense 什么是PRESENT PERFECT CONTINUOUS啊? write the sentence in the present perfect 用present perfect tense ,simple past tense , 求 4 个 present perfect progressive 句子 求 4 个 present perfect progressive 句子.. the present perfect tense的中文 here is my present()youA.toB.forC.inD.of present perfect continuous和present perfect simple的区别与用法 什么时候该用 present perfect 什么时候该用past simple? 求 past | past perfect | present perfact 的分别RT present perfect progressive 现在完成进行 和present perfect 有什么区别present perfect 加has/have+past participle 而present perfect progressive has/have+been+verb+ingparticiple 过去分词 use present perfect or simple past tenses:Theuse present perfect or simple past tenses:The Titanic.(sink) in 1912.