Modals - Degrees of Uncertainty

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Will / Might

Expressing degrees of certainty

Present & Future Uncertainty

VERY CERTAIN	UNCERTAIN	UNCERTAIN NEGATIVE
Use will or (be) going + verb to express certainty about a future activity, event.	Use may, might, could to express uncertainty, a guess, about a future activity, event.	Use may, might or an expression of doubt to indicate uncertainty about or likelihood of a future activity or event.
Polar bears will disappear. certainly	Polar bears may disappear. possibly	Polar bears may / might not disappear. possibly not
Polar bears are going to disappear. certainly	Polar bears might disappear. possibly	It is doubtful that polar bears will disappear. possibly not
	Polar bears can / could disappear. potentially	It is unlikely that polar bears will disappear. possibly not
The speaker is 100 % certain that they will disappear.	The speaker is uncertain they will disappear.	The speaker is uncertain they will not disappear.

guess (n.) – an attempt to answer a question or make a judgement when not sure whether it is correct
potentially (adv) – something that may become true in the future under the right (or wrong) conditions

Past Uncertainty

VERY CERTAIN - Reflection	UNCERTAIN - Speculation	UNCERTAIN NEGATIVE - Speculation
Use past tense to comment with certainty on a past activity or event.	Use may, might, could to express uncertainty, a guess, about the occurence of a past activity or event.	Use may have, might have or an expression of doubt to indicate uncertainty about the occurence of a past activity or event.
Dinosaurs disappeared due to a meteor strike.	Dinosaurs may have died from disease	They may not have had resistance to disease.
Dinosaurs died due to a global weather changes.	Dinosaurs might have died from starvation.	They might not have had enough to eat.
	Dinosaurs could have died from cosmic radiation.	They might not have had shelter from radiation.

reflection (n.) – remembering the past
speculation (n.) – an educated guess
resistence (n.) – ability to fight off

Sentence Types

Word Order

SENT TYPE	AUX VERB	SUBJECT	MODAL	VERB BASE	TAG CLAUSE
STATEMENT possibly		Polar bears	might	disappear.
possibly		Polar bears	may	disappear.
possibly		Polar bears	could	disappear.
QUESTION potentially	Could	Polar bears		disappear?
—	*Might	Polar bears		disappear?
—	*May	Polar bears		disappear?
possibly	Is it possible that	Polar bears	will	disappear?
TAG QUESTION —		Polar bears	might	disappear,	might they not?
—		Polar bears	may	disappear,	*may they not?
potentially		Polar bears	could	disappear,	could n't they?
possibly	It possible that	Polar bears	will	disappear,	isn't it?
NEGATIVE possibly not		Polar bears	might not	disappear.
possibly not		Polar bears	may not	disappear.
potentially not		Polar bears	could not	disappear.
possibly not	It is doubtful that It is unlikely that	Polar bears	will	disappear.
PAST past possibility		Scientists	might have	predicted this.
past possibility		Scientists	may have	predicted this. (but they didn't.)
lost opportunity		Scientists	could have	predicted this.
NEG. PAST past possibility		Scientists	might not have	predicted this.
past possibility		Scientists	may not have	predicted this.
an impossibility		Scientists	could not have	predicted this.
W / ADVERB possibly		We	might suddenly	lose this species.
possibly		We	may eventually	lose this species.
possibly		We	could also	lose this species.
possibly	It is possible that Possibly,	we	will soon	lose this species.

*awkward sounding
A tag question can also occur with a negative main sentence and a postive final question: Polar bears couldn't disappear, could they? Related page: And so / too

Related page: Modal Agreement

Practice 1

How Certain is the Speaker?

Decide what the meaning of the verb in the sentence is.

Select your response.
* indicates an incorrect response.

	FEEDBACK	YOUR RESPONSE
1	Stephen King's latest work could be a nightmare for book publishers. FEEDBACK 1	The writer is sure (about future event) The writer is uncertain (about future event) The writer is reflecting (on a past event)
2.	He will publish his books on the Internet. FEEDBACK 2	He is sure (about future event). He thinks so (about future event) . He is speculating (on a past event).
3.	The first chapter will be free, then he might ask readers to pay $1 for the next chapter. FEEDBACK 3	He is sure (about future event) . He is uncertain (about future event). He is speculating (on a past event) .
4.	If enough readers pay $1, he will write the next chapter in the series. FEEDBACK 4	This event is scheduled. This event is not scheduled.
5	In the past, King's dealings with publishers have been unsatisfactory. They might not have shared profits with him. FEEDBACK 5	The writer is sure (about future event). The writer is uncertain (about future event). The writer is speculating (on a past event).

Practice 2

Expressing Doubt and Certainty

Decide which modal can complete the sentence.

Select your response. * indicates an incorrect response.

Read the hint box for additional information.

#	FEEDBACK	YOUR RESPONSE
6.	The Internet many new writers to publish their works. FEEDBACK 6	will enable might enable might not enable
7.	Many writers how to present their materials on web sites. FEEDBACK 7	will know may know may not know
8.	Many people thought that copyright laws difficult to enforce. FEEDBACK 8	may be might be might have been
9.	Writers who publish on the Internet to profit from their web publishing. FEEDBACK 9	will expect may expect could expect
10.	Publishers trend in lower sales of printed books that is occuring now. FEEDBACK 10	might not predict may predict might not have predicted
11.	In the future, all books sold as digital copies to be read on handheld devices or to be printed on personal printers. WHY 11	may be sold might be sold will be sold
12.	Clearly, some people ready to give up a book that they can physically hold in their hands and turn its pages. FEEDBACK 12	may be may not be might not be