The auxiliary word which can be used only as a modal is may. The correct option is c.
An auxiliary (helping) verb known as a modal expresses the following: ability, possibility, permission, or obligation. Modal phrases (or semi-modals), which combine auxiliary verbs and the preposition to, are used to express the same ideas as modals.
Modal verbs express potential, intention, capacity, or necessity. They are used with the main verb of the sentence because they are a type of auxiliary verb (helper verb). Examples that are frequently used are should and must.
Therefore, the correct option is c. may.
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i believe the answer is C. Still and unmoving.
This invention also increased the number of available books.
A.
the number; modifies books
B.
also increased; modifies number
C.
This invention; modifies increased
D.
of available books; modifies number
D. books modify number
A verb is a word used to describe an action, state, or occurrence, and forming the main part of the predicate of a sentence, such as hear, become, happen! I believe the answer is Forecasted..