Modal verbs The place of modal verbs in the system of English verb
Modal verbs occupy a specific position in the system of the English verb. On the one hand, they possess lexical meaning of their own like notional verbs. On the other hand, they cannot be used in the sentence alone like functional verbs (auxiliaries and links).
Modal verbs are sometimes termed “defective” verbs because of their form:
they are followed by the Infinitive without the particle “to” (except ought to, to have to);
they don’t take -s (-es) in the 3 person singular, Present Indefinite tense;
they form interrogative and negative forms without the auxiliary do(does);
they have no verbals (the infinitive, participles or a gerund);
they have no analytical forms;
some of them lack the form of some tenses.
The term “modal” attached to these verbs is due to their meaning : these verbs do not denote any action or process, like the majority of the verbs but an attitude of the speaker to the action denoted by the following infinitive.
A modal verb in combination with the infinitive makes a compound modal verbal predicate.
We find the following modal verbs in English: can , may, must, shall, should, will, would, need, dare;
to be able to, to be allowed to, to be to, to have to are the equivalents of modal verbs.
1. It is important to note that all modal verbs show that an action is represented as necessary, (im)possible, desirable, doubtful, etc. from the point of view of the speaker. Consequently modal verbs are used in conversation. In past time contexts they may be found only in reported speech.
2. Different meanings of the modal verbs may be associated with different forms of the infinitive – simple and perfect, active and passive, common and continuous.
Simple (indefinite) infinitive is used when reference is made to the present.
I can’t promise you anything.
He may not know about it.
Perfect form of the infinitive is used when the action of the infinitive is referred to the past.
She can’t have said this.
He might have found the book in the library.
She could have explained the mystery.
The modal verb can
The modal verb can has the following forms : can for the present tense, could for the past tense, to be able to is used to supply the missing forms. The form could may be used in two ways:
a) as a form of the past tense of can indicative mood in past time contexts: He could speak English when he was a child. She could paint landscapes.
b) in present time contexts to express unreality as a form of the subjunctive mood : He could do it if he had time.
Can has the following meanings :
Ability, capability (physical or mental)
He can read a little French. The child can’t carry the heavy bag
In this meaning the phrase to be able to is used in all tense – forms if necessary.
I’m not able to shift the bolts on the wheel. I’ll have to get help. She was ill and was not able to walk. He will be able to write to us from Portugal.
If reference is made to the present or future, can is followed by the indefinite (simple) infinitive.
Can you write with your left hand ? We can discuss your paper after lunch.
However, if the time reference is not clear from the context or if it is necessary to stress that the action refers to the future, shall/will + be able to is used. I shall be able to earn my living soon.
If there is no indication of the past time in the context but the speaker wishes to refer the action to the past, was/were able is used instead of could to avoid ambiguity .
She was able to explain the mistery.
In combination with the perfect infinitive could indicates that the action was not carried out in the past.
She could have explained the mistery.
Possibility due to circumstances
You can see the forest through the open window.
In this meaning can is followed by the simple infinitive and it refers the action to the present or future.
Where can she be ? We can’t use the indefinite article here. Such problems can be solved easily.
The form could in combination with the simple or perfect infinitive may also express unreality with reference to the present or future (simple infinitive) or to the past (perfect infinitive) – Subjunctive mood.
You could see the house from here if it were not so dark. You could have seen the house if it had not been so dark.
Permission (in the negative form - prohibition)
You can use my car. Can I take your dictionary ?
In this meaning can is combined only with the simple infinitive. The form could with reference the present is found only in interrogative sentences to express a more polite request (subjunctive mood):
Could I use your car ?
The form could is also found in reported speech in accordance with the rules of the sequence of tenses – the indicative mood, past tense: He said I could use his car. He asked me if he could take my pen.
Uncertainty, doubt.
In this meaning can is found only in interrogative sentences (general questions). Sentences of this kind are emotionally coloured and so their application is rather restricted. Depending on the time reference, can in this meaning is combined with different forms of the infinitive: Can he really be ill?
Can it be so late? Can she have said it? Can they have been waiting for us so long?
Could implies more uncertainty. In Russian such sentences are rendered by the word неужели.
Improbability
He can’t be more than forty.
In this meaning can is found only in negative sentences and is rendered in Russian by – He может быть, невероятно. In the meaning of improbability can is used with different forms of the infinitive depending on the time reference: He can’t be really ill. She can’t have said it. They can’t have been waiting for us so long. She couldn’t be telling lies.
Could is used to make the statement less categorical.
Notice the following set phrases with the verb can :
Can’t help + gerund
She can’t help crying.
Can’t help doing smth means не могу не удержаться, не могу не… .
Can’t but do smth …
I can’t but ask him about it – ничего другого не остается, как спросить его об этом.