The
Holy Modal Rounders (wiki link) were a fine and folksy New York City band. They had nothing to do with modal verbs, but wouldn't it be nice if they did? Because should/could/would/can/may and so on are all modal verbs, and very interesting indeed. If you're a grammar nerd, know your modals.
Verbs in English have many parts. To show tense, voice, and mood, we add the appropriate forms of the auxiliary verbs "to be," "to have," and "to do." (We also use "will" for future tenses.)
To make requests, give instructions, or show doubt, certainty, necessity, obligation, possibility, or probability, we add the modal auxiliary verbs, those sometimes perplexing coulds, woulds, shoulds, mights, and cans.
One perplexity solved: "Should of," "would of," and "could of," as well as "shoulda, woulda, coulda," are idiomatic spellings of "should have," "would have," and "could have." Such spellings are usually avoided by writers and editors of formal edited English unless the specific intent is to reproduce standard speech patterns. Thus, in print they are often more acceptable in dialogue than in narrative, but even in dialogue, some editors and writers prefer to standardize them to "have."
What about other perplexities?
Here's a hint to what is going on. Technically, modal verbs have present/past forms.
Shall is present, should is past; can is present, could is past: may is present, might is past; will is present, would is past.
Here's a useful table:
Auxiliary Verbs Modal Auxiliary Verbs
be have shall may
am has should might
is had must
are having
was will can
were do would could
been does
being did
However, modern English usage has evolved away from such strict definitions.
Should, could, and would also indicate conditional states, leading us into a murky swamp of grammar. Some grammarians hold that the conditional is a voice, others that it is not a voice, tense, or even mood.
Let's not delve into such murky waters today. Let's look at "Mother, may I?"
Formal edited English requires that can be used only to indicate ability and may be used only to indicate permission. Spoken English very seldom observes this distinction. Check the context of the prose and, if you are editing, check with the author if you plan to observe the distinction between can and may in your writing or editing.
And there actually is a difference between may and might.
May indicates possibility
"It may rain." (It is possible or even probable that rain will fall.)
Might often functions as a weaker form of may.
"I may win the lottery."
sounds like a stronger possibility than
"I might win the lottery."
Technically, might is the past of may. However, either form is used in the present tense in modern formal American English.
HOWEVER: If a sentence contains more than one verb and that other verb or those other verbs are in the past tense, then only the might form should be used.
She thought she might have twisted her knee.
Eileen said she might leave before 5 pm.
Hmm. That sounds like sequence of tenses stuff. . . . In this sequence of grammar posts, perhaps that's next?
