Question

What is the function of used to in modal auxiliary?.

Answer 1

Modal auxiliary verbs include: can, could, may, might, must, ought, shall, should, will, and would. These verbs - which never change forms the way most other verbs do - indicate possibility, capability, necessity, or willingness. ... Modal auxiliary verbs are quite useful, and they serve an important function in writing.

Answer 2

Modal verbs are used in conjunction with verbs to express their function. Examples are permission, obligation, lack of necessity, possibility, ability, prohibition, advice and probability. ... They should always be followed by the base verb word (infinitive) like, play, work, run, and eat.