3rd year Modal Verbs AND phrases of obligation/necessity
STRONG OBLIGATION
HAVE TO
DON’T HAVE TO
DO YOU HAVE TO?
General obligation
ABSENCE of
Question regarding
from external
obligation/necessity
obligation from
authority
external authority
MUST
Personal specific
obligation
FORCED TO
MUSTN’T
Specific OR general
obligation NOT to
do something – for
FORBIDDEN
activities
NOT FORCED TO
Used in all tenses
MUST YOU?
Question regarding
personal specific
obligation
Only in present
tense
ARE YOU FORCED
TO
Used in all tenses
WEAKER OBLIGATION (advice, moral obligation, opinion)
SHOULD
advice, moral
obligation, opinion
OUGHT TO
advice, moral
obligation, opinion
BE SUPPOSED TO
Something you are
expected to do
HAD BETTER
Something it would
be better to do
SHOULDN’T
SHOULD YOU?
past form: should
have + pp
OUGHTN’T TO
OUGHT YOU TO?
past form: ought to
have + pp
BE NOT SUPPOSED
TO
ARE YOU SUPPOSED
TO
HAD BETTER NOT
HAD YOU BETTER?
past form: was
supposed to/ is
supposed to have
-
NECESSITY
NEED TO
Necessity
DON’T NEED TO/
NEEDN’T
Absence of necessity
DO YOU NEED TO?
Question regarding
necessity
* Needn’t have refers to something you did unnecessarily in the past.
PAST FORM: DIDN’T
NEED TO/* NEEDN’T
HAVE +PP