- must indicate logical conclusions and logical guesses
(a) Events in the present
----- Don't use infinitive
must + be + .... ing
must + be + adjective
(ex) "Her line is busy" "Maybe she must be
using the telephone now"
(ex) ASA is not here; She must be sick now.
(b) Events in the past ----- Don't use should, if you use should, the sentence
will have different meaning.
must + have + past participle
(ex) Today examination is very difficult; You must have not
studied before examination.
(ex) She looks like very sleepy; She must have not slept last night.
(c) Events that repeat ----- Don't use ....ing and infinitive
must + verb word
(ex) Every day Asa is late ; She must go to bed late every night.
(ex) Ken always gets bad point ; She must not study a lot.