This document provides examples of how to use should, shouldn't, must, and mustn't to express obligations, advice, or necessity. It also gives examples of fill-in-the-blank sentences to practice using these words correctly. Additionally, it summarizes rules for using if/when conditional sentences and the words too, too much, too many to indicate an excessive amount and enough/not enough to refer to sufficient or insufficient amounts.

15. SHOULD- SHOULDN´T- MUST We use shouldtosuggestanobligation. He shouldspend more time in hishomework.Shouldn´tisusedtogiveanadvice. I thinkyoushouldn´tgoout becase itisraining.MUSTItisusedtoexpressnecessityorstrongobligation.ExpressionsforordersancommandsYoumustarriveearlytonight.Youmustbringyourhomeworktomorrow

16. . Writeshould, shouldn´t , mustormustn´twhereitcorrespondsYou ___________writeyourexerciseswithink.You ____________ smoke in a closedarea.You ____________ arivetoclasson time.Helen __________ see a doctor becausesheissick.You __________ finishyourworkbeforeyougo.We_________be more carefulwiththewater.We ________speak in English in cass.They __________speak in class.Carlos __________paytherenton time.The bus ____________arrive at o´clock.

17. FIRST CONDITIONALThe conditional sentences consist of two parts: The if – clause ( hypothesis ) , and the main clause.If he wakes up , he will miss the plane The first conditional express a real or very probable situation in the present or the future.The sentences not always begin with the if clause.He will miss the plane , if he wakes up.

18. IF - WHENWe use when in conditionals to show that we are sure that something will happen. I´ll see you when I come to Pachuca.We use if in conditionals to show that we are not sure whether something will or not happen. I´ll see you if I come to Pachuca.

19. too , too much , too many We use these words to say that something is more than we wanted.I´ll try not to get too late.He ´s got too much work to do.I´ve always got too many things to do.

20. Enough – not enough We use enough to say something is the correct number or amount. I have enough money to buy this car. I thing this flat is big enough for you and me.We use not enough to say something is less than we wanted. The baby isn´t old enough to talk. I don´t have enough money to buy the car.