Which of the following is not correct with reference to Modal Auxiliary Verbs?
1
Modal Auxiliary verbs are not used as main verbs.
2
Modal Auxiliary verbs are not used in V1, V2, V3, ing or s/es form.
3
Modal Auxiliary verbs change their forms according to subject, person or tense.
4
Modal Auxiliary verbs 'ought' and 'used' always preceede infinitve 'to + base form of verb'.