A practical english grammar - Vyssaja skola 1978
Chapter 8 - The modals
Sound symbols
Modals are a class of auxiliary verbs that combine with the base form of a following verb to make verb phrases with a wide variety of meanings. The modal auxiliaries are can, could, will, would, may, might, shall, should, and must, as well as some other expressions like ought to, had better, would (or had) rather, which behave like modals and have similar kinds of meaning.
The modals exist in one form only. None of them has an s-form or an ing-form, and, although could, would, might, and should are usually considered the past tense of can, will, may, and shall, respectively, it is more convenient to treat each modal as a separate item. As will be seen, these words do not always mean “past” of anything, but have independent meanings of their own.
Modals in the affirmative are usually spoken with weak stress. Will contracts to ’ll and would to’d after the subject pronouns. The combination of modals and n’t are given on page 69.
A generalized description of the meaning of the modals would be quite difficult and is beyond the scope of this book. Suffice it to say at this point that the modals express non-actual situations. They do not deal with objective events except by implication;1 instead, they report opinions, judgments, possibilities, intentions, probabilities, obligations, and so оn.
There are some ordinary verbs that are followed by to and another verb (have to, be going to, be supposed to, etc.) whose meaning is sometimes very similar to that of certain of the modals. These verbs will be discussed in Chapter 10.
The modals in common use, with examples of their various meanings, are presented in the following pages. The student will find that the grammar of the modals is extremely simple; it is their meaning that causes difficulty.
1 “We could hear someone coming upstairs.” It is true that this sentence communicates to almost everybody that we actually did hear someone, and is thus equivalent to “We heard someone coming upstairs.” This is through the connotation, however, and not the denotation of the modal. Could in itself states nothing more than the potentiality of our hearing.