|The verbs can, could, will, would, should, may, might, must, ought and shall are verbs which 'help' other verbs to express a meaning: it is important to realise that these "modal verbs" have no meaning by themselves. A modal verb such as would has several varying functions; it can be used, for example, to help verbs express ideas about the past, the present and the future.|
Basic grammatical rules
|1 Modal verbs are NEVER used with other auxiliary verbs such as do, does, did etc. The negative is formed simply by adding "not" after the verb; questions are formed by inversion of the verb and subject:|
|You should not do that.|
Could you pick me up when I've finished?
2 Modal verbs NEVER change form: you can never add an "-s" or "-ed", for example.
3 Modal verbs are NEVER followed by to, with the exception of ought to.
Modals give to other verbs sort of meanings
The meaning are usually connected with ideas of DOUBT, CERTAINTY, POSSIBILITY and PROBABILITY, OBLIGATION and PERMISSION (or lack of these). You will see that they are not used to talk about things that definitely exist, or events that definitely happened. These meanings are sometimes divided into two groups:
DEGREES OF CERTAINTY: certainty; probability; possibility; impossibility
OBLIGATION/FREEDOM TO ACT: permission,lack of permission; ability; obligation.
• He should be here by now.
• I could swim quite well when I was younger.
• You mustn’t blame yourself for this.
• You might have discussed it with me first.
• You can’t be serious!
• Could you open the window please?
• Must you make so much noise?
• She had to take her brother along with her.
• We ought to be going.
• They have to be more punctual.
• He has to take responsibility for the accident.
• I had to help my father repair his car.
• We will have to put this off until tomorrow.
• You shouldn’t have to suffer in silence.
• You don’t have to come if you don’t want to.
• He didn’t have to do all the shopping.
• You ought to see a doctor.
• You should see a doctor.
• They ought to have got back home by now.
• They should have got back home by now.
• It might take more than a week. (possibility)
• You might have told me about it! (showing disapproval)
• He must take his medicine three times a day. (obligation)