Modals/ Modal verbs / Modal Auxiliaries

eg1471/jc/dec2008 Forms of Modals Modals do not take on -s as they do not indicate number or person. The nurse can give the injection. The computers will process the information. The base form of the verb is used after the modal verb. The planes must take off now. The wastage can be stopped. The technical glitch could have been avoided.

eg1471/jc/dec2008 Forms of Modals When modals take on the negative not, the latter follows the modal even when be or have are present. The investigation may not end today. The survey should not have yielded such skewed results. The gamers could not be there at this hour. Do not use the contracted forms of negative modals in formal writing. Use cannot and not can not .

eg1471/jc/dec2008 Uses of Modals To express ability To express degrees of possibility To express advisability To express necessity or lack of necessity

eg1471/jc/dec2008 Modals Expressing Ability ModalsMeaningExample CanExpress physical ability or skill or the lack of it The new employee can drive. The astronaut cannot go up the space shuttle today. CouldExpress a past ability or skill and a lack of it in the past In the 1900s, people could not communicate with each other across the globe via telecommunication. Could have + past participle Refers to a past situation in which the ability for something to happen existed, but the reverse happened. The team could have been the champions.

eg1471/jc/dec2008 Modals Expressing Degrees of Possibility cannot may/might not should must Unlikely highly likely To express impossibility or near impossibility, use cannot. To express low possibility, use may/may not; might/ might not; or could/ could not. To express moderate possibility, use should/ should not. To express high possibility or probability, use must. To express certainty or human intentions, use will/ will not. In the past context, use would/ would not. See Raimes (2006) pp for examples

eg1471/jc/dec2008 Modals Expressing Advisability To express whether something is a good idea or not, use should or should not. To express an advisable action that did not occur in the past, use should have + past participle. To express a past action that was not advisable, use should not have + past participle.

eg1471/jc/dec2008 Modals Expressing Necessity or Lack of Necessity To express necessity, use must or the phrasal verbs has/have to. To express lack of necessity, use the phrasal alternative do/does/did have to. To express a necessity in the past, use had to. Must not expresses a prohibition, not a lack of necessity.

eg1471/jc/dec2008 Phrasal Alternatives to Modal Auxiliaries MeaningModal AuxiliaryPhrasal Alternative certaintywillbe going to abilitycanbe able to advisabilityshouldhad better, ought to necessitymusthave to, have got to, be supposed to past necessityhad to lack of necessitydo not have to

eg1471/jc/dec2008 Sources Lane, A. and Lange, E. (1999). Writing Clearly: An Editing Guide (2 nd ed.). Boston: Heinle and Heinle Publishers, Raimes, A. (2006). Grammar Troublespots: A Guide for Student Writers (3 rd ed.). New York: Cambridge University Press,