Modal Auxiliaries

Modal Auxiliaries

 A modal verb (also ‘modal’, ‘modal auxiliary verb’, ‘modal auxiliary’) is a type of verb that is used to indicate modality – that is, likelihood, ability, permission, and obligation. Examples include the English verbs can/could, may/might, must, will/would, and shall/should.

Helping verbs or auxiliary verbs such as will, shall, may, might, can, could, must, ought to, should, would, used to, need are used in conjunction with main verbs to express shades of time and mood. The combination of helping verbs with main verbs creates what are called verb phrases or verb strings.

Uses of Shall and Will and Should

In England, shall is used to express the simple future for first person I and we, as in "Shall we meet by the river?" Will would be used in the simple future for all other persons. Using will in the first person would express determination on the part of the speaker, as in "We will finish this project by tonight, by golly!" Using shall in second and third persons would indicate some kind of promise about the subject, as in "This shall be revealed to you in good time." This usage is certainly acceptable in the U.S., although shall is used far less frequently. The distinction between the two is often obscured by the contraction 'll, which is the same for both verbs.
In the United States, we seldom use shall for anything other than polite questions (suggesting an element of permission) in the first-person:

• "Shall we go now?"
• "Shall I call a doctor for you?"

(In the second sentence, many writers would use should instead, although should is somewhat more tentative than shall.) In the U.S., to express the future tense, the verb will is used in all other cases.

Shall is often used in formal situations (legal or legalistic documents, minutes to meetings, etc.) to express obligation, even with third-person and second-person constructions:

• The board of directors shall be responsible for payment to stockholders.
• The college president shall report financial shortfalls to the executive director each semester."

Should is usually replaced, nowadays, by would. It is still used, however, to mean "ought to" as in

• You really shouldn't do that.
• If you think that was amazing, you should have seen it last night.

In British English and very formal American English, one is apt to hear or read should with the first-person pronouns in expressions of liking such as "I should prefer iced tea" and in tentative expressions of opinion such as

• I should imagine they'll vote Conservative.
• I should have thought so.

Uses of Do, Does and Did

In the simple present tense, do will function as an auxiliary to express the negative and to ask questions. (Does, however, is substituted for third-person, singular subjects in the present tense. The past tense did works with all persons, singular and plural.)

• I don't study at night.
• She doesn't work here anymore.
• Do you attend this school?
• Does he work here?

These verbs also work as "short answers," with the main verb omitted.

• Does she work here? No, she doesn't work here.

With "yes-no" questions, the form of do goes in front of the subject and the main verb comes after the subject:

• Did your grandmother know Truman?
• Do wildflowers grow in your back yard?

Forms of do are useful in expressing similarity and differences in conjunction with so and neither.

• My wife hates spinach and so does my son.
• My wife doesn't like spinach; neither do I.

Do is also helpful because it means you don't have to repeat the verb:

• Larry excelled in language studies; so did his brother.
• Raoul studies as hard as his sister does.

The so-called emphatic do has many uses in English.

1. To add emphasis to an entire sentence: "He does like spinach. He really does!"
2. To add emphasis to an imperative: "Do come in." (actually softens the command)
3. To add emphasis to a frequency adverb: "He never did understand his father." "She always does manage to hurt her mother's feelings."
4. To contradict a negative statement: "You didn't do your homework, did you?" "Oh, but I did finish it."
5. To ask a clarifying question about a previous negative statement: "Ridwell didn't take the tools." "Then who did take the tools?"
6. To indicate a strong concession: "Although the Clintons denied any wrong-doing, they did return some of the gifts."

In the absence of other modal auxiliaries, a form of do is used in question and negative constructions known as the get passive:

• Did Rinaldo get selected by the committee?
• The audience didn't get riled up by the politician.

Uses of Have, Has and Had

Forms of the verb to have are used to create tenses known as the present perfect and past perfect. The perfect tenses indicate that something has happened in the past; the present perfect indicating that something happened and might be continuing to happen, the past perfect indicating that something happened prior to something else happening. (That sounds worse than it really is!) See the section on Verb Tenses in the Active Voice for further explanation; also review material in the Directory of English Tenses.

To have is also in combination with other modal verbs to express probability and possibility in the past.

• As an affirmative statement, to have can express how certain you are that something happened (when combined with an appropriate modal + have + a past participle): "Georgia must have left already." "Clinton might have known about the gifts." "They may have voted already."
• As a negative statement, a modal is combined with not + have + a past participle to express how certain you are that something did not happen: "Clinton might not have known about the gifts." "I may not have been there at the time of the crime."
• To ask about possibility or probability in the past, a modal is combined with the subject + have + past participle: "Could Clinton have known about the gifts?"
• For short answers, a modal is combined with have: "Did Clinton know about this?" "I don't know. He may have." "The evidence is pretty positive. He must have."

To have (sometimes combined with to get) is used to express a logical inference:

• It's been raining all week; the basement has to be flooded by now.
• He hit his head on the doorway. He has got to be over seven feet tall!

Have is often combined with an infinitive to form an auxiliary whose meaning is similar to "must."

• I have to have a car like that!
• She has to pay her own tuition at college.
• He has to have been the first student to try that.

Other helping verbs, called modal auxiliaries or modals, such as can, could, may, might, must, ought to, shall, should, will, and would, do not change form for different subjects. For instance, try substituting any of these modal auxiliaries for can with any of the subjects listed below.

Uses of Can and Could

The modal auxiliary can is used

• to express ability (in the sense of being able to do something or knowing how to do something):
  He can speak Spanish but he can't write it very well.
• to expression permission (in the sense of being allowed or permitted to do something):
  Can I talk to my friends in the library waiting room? (Note that can is less formal than may. Also, some writers will object to the use of can in this context.)
• to express theoretical possibility:
  American automobile makers can make better cars if they think there's a profit in it.

The modal auxiliary could is used

• to express an ability in the past:
  I could always beat you at tennis when we were kids.
• to express past or future permission:
  Could I bury my cat in your back yard?
• to express present possibility:
  We could always spend the afternoon just sitting around talking.
• to express possibility or ability in contingent circumstances:
  If he studied harder, he could pass this course.

Can versus May

Whether the auxiliary verb can can be used to express permission or not — "Can I leave the room now?" ["I don't know if you can, but you may."] — depends on the level of formality of your text or situation. As Theodore Bernstein puts it in The Careful Writer, "a writer who is attentive to the proprieties will preserve the traditional distinction: can for ability or power to do something, may for permission to do it.
The question is at what level can you safely ignore the "proprieties." Merriam-Webster's Dictionary, tenth edition, says the battle is over and can can be used in virtually any situation to express or ask for permission. Most authorities, however, recommend a stricter adherence to the distinction, at least in formal situations.

Uses of May and Might

Two of the more troublesome modal auxiliaries are may and might. When used in the context of granting or seeking permission, might is the past tense of may. Might is considerably more tentative than may.

• May I leave class early?
• If I've finished all my work and I'm really quiet, might I leave early?

In the context of expressing possibility, may and might are interchangeable present and future forms and might + have + past participle is the past form:

• She might be my advisor next semester.
• She may be my advisor next semester.
• She might have advised me not to take biology.

Avoid confusing the sense of possibility in may with the implication of might, that a hypothetical situation has not in fact occurred. For instance, let's say there's been a helicopter crash at the airport. In his initial report, before all the facts are gathered, a newscaster could say that the pilot "may have been injured." After we discover that the pilot is in fact all right, the newscaster can now say that the pilot "might have been injured" because it is a hypothetical situation that has not occurred. Another example: a body had been identified after much work by a detective. It was reported that "without this painstaking work, the body may have remained unidentified." Since the body was, in fact, identified, might is clearly called for.

Uses of Will and Would

In certain contexts, will and would are virtually interchangeable, but there are differences. Notice that the contracted form 'll is very frequently used for will.

Will can be used to express willingness:

• I'll wash the dishes if you dry.
• We're going to the movies. Will you join us?

It can also express intention (especially in the first person):

• I'll do my exercises later on.

and prediction:

• specific: The meeting will be over soon.
• timeless: Humidity will ruin my hairdo.
• habitual: The river will overflow its banks every spring.

Would can also be used to express willingness:

• Would you please take off your hat?

It can also express insistence (rather rare, and with a strong stress on the word "would"):

• Now you've ruined everything. You would act that way.

and characteristic activity:

• customary: After work, he would walk to his home in West Hartford.
• typical (casual): She would cause the whole family to be late, every time.

In a main clause, would can express a hypothetical meaning:

• My cocker spaniel would weigh a ton if I let her eat what she wants.

Finally, would can express a sense of probability:

• I hear a whistle. That would be the five o'clock train. 

Uses of Used to

The auxiliary verb construction used to is used to express an action that took place in the past, perhaps customarily, but now that action no longer customarily takes place:

• We used to take long vacation trips with the whole family.

The spelling of this verb is a problem for some people because the "-ed" ending quite naturally disappears in speaking: "We yoostoo take long trips." But it ought not to disappear in writing. There are exceptions, though. When the auxiliary is combined with another auxiliary, did, the past tense is carried by the new auxiliary and the "-ed" ending is dropped. This will often happen in the interrogative:

• Didn't you use to go jogging every morning before breakfast?
• It didn't use to be that way.

Used to can also be used to convey the sense of being accustomed to or familiar with something:

• The tire factory down the road really stinks, but we're used to it by now.
• I like these old sneakers; I'm used to them.

Used to is best reserved for colloquial usage; it has no place in formal or academic text.

What to keep in mind when using modals

Explanation	Sample sentences
Do not use modals for things which happen definitely.	The sun rises in the east. - A modal can't be used in this sentence.
They have no -s in the 3rd person singular.	He can play football.
Questions are formed without do/does/did.	Can he speak Spanish?
It follows a main verb in its infinitive.	They must read the book.
There are no past froms (except could and would).	He was allowed to watch the film.
When you use the past particple you tell about things which did not happen in the past.	You should have told me.

Long and contracted forms of modals

Affirmative		Negative
Long forms	Contracted forms	Long forms	Contracted forms
can	--	cannot	can't
could	--	could not	couldn't
may	--	may not	--
might	--	might not	--
ought to	--	ought not to	oughtn't to
need	--	need not	needn't
shall	'll	shall not	shan't
should	'd	should not	shouldn't
will	'll	will not	won't
would	'd	would not	wouldn't

Exercises:

Q1.	I didn’t feel very well yesterday. I couldn’t eat anything.
		cannot
		couldn’t
		mustn’t

---

Q2.	You should look at me when I am talking to you.
		could
		should
		would

---

Q3.	I was using my pencil a minute ago. It must be here somewhere!
		can
		could
		must
		would

Q4.	You really must not be late again.
		must not
		don’t have to be

---

Q5.	If you don’t start working harder, you ..... repeat the course next year.
		have to
		must
		will have to

---

Q6.	His parents spoil him. He’s always ..... to do whatever he wants.
		been able
		been allowed

---

Q7.	Phone her now. She ..... home by now.
		has to be
		must be
		would be

---

Q8.	You ..... forget your sun cream. It’s going to be very hot!
		don’t have to
		mustn’t
		needn’t

---

Q9.	I ..... be able to help you, but I’m not sure yet.
		might
		would

---

Q10.	Entrance to the museum was free. We ..... pay to get in.
		needn’t
		didn’t need to

---

Q11.	Already as a child Mozart ..... play the piano beautifully.
		could
		should
		would

---

Q12.	Which sign are you more likely to see at an airport: Bags ..... not be left unattended.
		can
		must
		may

---

Q13.	I really ..... try to get fit.
		may
		must
		would

---

Q14.	..... take a photograph of you?
		Am I allowed to
		May I

---

Q15.	Students ..... borrow up to 6 books at any time.
		are allowed to
		could

---

Q16.	Whose is this bag? - I don’t know, but it ..... belong to Yuta.
		could
		may
		should
		would

---

Q17.	..... I go to the bathroom, please?
		May
		Must
		Would

---

Q18.	His excuse ..... be true, but I don’t believe.
		can
		may

---

Q19.	It’s very important to ..... speak more than one language.
		can
		be able to

---

Q20.	I don’t like ..... get up early on a Sunday.
		being able to
		being allowed to
		having to

Sources:
 http://www.englisch-hilfen.de/en/grammar/hilfsverben1.htm
http://grammar.ccc.commnet.edu/grammar/auxiliary.htm 
http://esl.fis.edu/grammar/multi/modal1.htm