19. Ways of expressing obligation, necessity, supposition

19. Ways of expressing obligation, necessity, supposition

FUNCTION	VERB	INFINITIVE	USAGE	EXAMPLES
obligation	shall (compulsion, strict order)		2^nd and 3^rdpersons	What a mess! You shall do up now!
should (advisability, desirability)	+ / -- /?	simple	reference to the future	We should discuss the matter over.
simple / continuous	reference to the present (stative / durative verbs)	You should be doing up accurately.
+	perfect	desirable action wasn’t fulfilled	You should have accepted the offer.
--	perfect	undesirable action was fulfilled	You shouldn’t have bought this awful sofa.
have to (imposed by the circumstances)	simple	+ /?	We have to hurry up a bit.
be to (due to the arrangement)	+ /?	simple	present or past actions	I am to be there at 10.
perfect	unfulfilled plan	He was to have been there at 10.
ought to (advisability, desirability)	+ / -- /?	simple	reference to the future	You ought to visit granny.
simple / continuous	reference to the present (stative / durative verbs)	You ought to be studying hard.
+	perfect	desirable action wasn’t fulfilled	You ought to have kept this secret to yourself.
--	perfect	undesirable action was fulfilled	You oughtn’t to have shouted at your mother.
must (from the speaker’s point of view)	+ /?	simple	duty, necessity	You must study hard to get a good job.
necessity	must	=	=	=	=
to have to	=	=	=	=
to be to	=	=	=	=
should	=	=	=	=
ought to	=	=	=	=
supposition	might (less certain)
may (implying uncertainty)	+ / --	simple	reference is made to the future	He may find it there.
simple	reference is made to the present	He may be there.
continuous	=, dynamic verbs	He may be sleeping.
perfect	reference is made to the past	He may have forgotten about the meeting.
perfect continuous	=, dynamic verbs	He may have been sleeping.
can (possibility due to circumstances)	simple	reference is made to the present and future	The light in the opposite window is on, and I can see a person walking in the room.
could (=)	simple	reference is made to the past	She could see what was written there as the letters were big enough.
simple	to express unreality with reference to the present and future	She could phone him if it were not so late.
perfect	the action that wasn’t fulfilled in the past	She could have phoned him if it hadn’t been so late.
will	simple	reference to the present or future	This will be his brother, I suppose.
perfect	reference to the past	He will have revealed the truth, I believe.
should (implying strong probability)		not very common – mostly MUST is used.	This party should be great.
ought to (=)		Not very common – mostly MUST is used. Set phrases: you ought to know; you ought to be ashamed of yourself	This party ought to be great.
must (implying strong probability)	+	simple	With stative verbs (present)	He must believe it.	restrictions
continuous	With dynamic verbs (present)	He must be working.
perfect	Past action	He must have finished it.	not used to express future; used only in +, not in – and?
perfect continuous	The action began in the past and continues into the moment of speaking	He must have been working the whole day. He looks tired.

Deduction chart:

Might ð may ð could (can) ð will, should, ought to ð must ð is

Дата добавления: 2015-09-29