the Present Perfect Tense 现在完成时现在完成时的构成: have / has + 动词过去分词 时间状语:already , yet , ever , never , just , before 规则动词的过去分词: 1)一般加+ ed: worked, started 2) “辅音+y”结尾的动词,y 变成i后加ed: study-studied 3)以“e”结尾的动词后加 “d”: hope-hoped 4)双写 辅音字母:stopped 动词过去分词形成方式: 规则和不规则变化动词的过去式以及过去分词 不规则动词的过去式与过去分词: AAA: put put put letlet let ABB: standstood stood ABA: becomebecamebecome ABC: eat ateeaten现在完成时的不同的形式: 肯定式:主语+has/have+过去分词(p.p.) +. My sister has already washed all the clothes. 否定式:主语+hasnt+(p.p.)+. My sister ha