How we change what others think, feel, believe and do
Imperative with verbs
Use modal verbs (e.g. can, may, could, ought, should, must) to show how important and necessary something it. This may include making something more important or less important depending on where the other person is and where you think they should (!) be.
You know you must do this today.
I know I should help you, but I am busy.
Jim said you ought to do it today, and it must be done this week.
Imperative forms create motivation through triggering associations of necessary action that people have associated with the words. Thus, when you say 'should', the other person may well feel a sense of obligation. They may also, of course, react against a strong imperative and you need to sense the best form to use.
Where the other person is strongly opposed to your ideas, it is often a good idea to start by moving them into realms of possibility before 'going for the kill' with imperative language.
It is easy in imperatives to fall into floppy language and not give as strong an imperative as you should. Thus a 'must' becomes a 'should' and a 'should' becomes a 'could'.
Legal and standards documents often use 'shall' and 'will' to indicate imperative.
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