Question

All modal verbs have some special characteristics transcribe the best option to complete each of the following sentences.
a) Modal verbs are used before the infinitive with/ without to of another verb, to modify its meaning

b) We add/ do not and s in the third person singular

c) They are used/ are not used with do when forming negatives or in questions

Answer 1

a - without to

b - do not add "s"

c - are not used with do