past continuous: aff:i was listening, you were listening. neg:i wasn't listening, you weren't listening. int: was i listening? were you listening? present perfect: aff: subject + have/has + the past participle neg: subject + haven't/hasn't + the past participle int: have/has + subject + the past participle. first conditional: if + frase en present simple, sujeto + will + frase simple. too and enough: too= demasiado y va delante dl adjetivo, enugh= suficiente y va en lo ultimo, despue dl adjetivo. have to: aff: i have to study, he has to study, neg: i don't have to, she doesn't have to int: do i have to..? does he have to..? since and for: since es cuando se marca un punto en el tempo y for es por un periodo d tempo. passive: act: they sent the letter on tuesday, pass: the letter was sent on tuesday. passive ( present simple): present tense of to be + past participle of the main verb. passive ( past simple): past tense of to be + past participle of the main verb. second conditional: if + frase en past simple + would + verb. indefinite pronouns: someone and something en frases aff, y anyone y anything en negative and interr.