1. The Present Perfect Formación: (+) SUBJECT+ HAVE / HAS+ VERB PAST PARTICIPLE + ... I have already written the letter. ( - ) SUBJECT + HAVEN´T/HASN´T + VERB PAST PPLE.… I haven´t written the letter yet. ( ? ) HAVE/ HAS + SUBJECT+ VERB PAST PPLE. + ... Have you written the letter yet?