e. Conditional certainty or possibility: would, wouldn’t, could,
couldn’t, might, mightn’t.
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Here are the explanations from several statements above about the usages of those modal auxiliaries, among them:
a. Can
Can is used informally to request permission, especially if the speaker is
talking to someone shehe knows fairly well.
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The detail functions of Can
are followed: 1.
To express the ability
E.g.: I can speak three foreign languages. He can swim
2. To express request or asking to someone else for doing something.
E.g.: Can you open the windows? Can you help me?
3. To express asking or giving permission.
Giving Permission:
E.g.: You can go home now. You can smoke here.
Asking Permission:
E.g.: Can I go home now? Can I use your dictionary?
4. To express possibility
E.g.: He can be a good doctor in the future.
5. To express offering something to someone else
E.g.: Can I get you some tea?
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51
Michael Swan, Practical English Usage, Oxford: Oxford University press, 1980, p. 389.
52
Betty Schramfer Azar, Understanding and Using English Grammar 2
nd
Edition, … p. 68.
53
Silvester Goridus Sukur, Complete English Grammar for the TOEFL, Yogyakarta: Indonesia Cerdas, 2007, p. 116.
b. Could
1.
Could expresses ability, subject to certain conditions which probably do not exist. In this use, could can refer to the present, the past, or the future.
E.g.: I could go know, if I wanted to. I do not want to
2.
Could is used to request permission. It is somewhat more formal and
polite than can.
E.g.: Could I borrow your pencil?
3.
Could also express the ability in the past time. E.g.: When I was younger, I could run fast.
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c. May
1.
May express possibility. E.g.: I may
go, but I don‟t really want to.
It may rain, according to the weather report.
2.
May is also used to express permission. It is considered more formal and
polite than can or could.
E.g.: May I smoke here? No, you may not.
d. Might
1.
Might expresses possibility which is considerably slighter or weaker than that express by may.
E.g.: I might
accompany you, but it doesn‟t appear very likely.
It might snow in October; you can never be sure.
2.
Might is used to ask permission. It is more formal and more polite than
may, can, or could.
E.g.: Might I be excused early?
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54
George E. Wishon, Julia M. Burks, Let’s write English revised edition, New York: Litton
Educational Publishing, 1980, p. 230.
55
George E. Wishon, Julia M. Burks, Let’s write English revised edition, … p. 232.
