Max verbs consecutively after the subject of a sentence

[David30]

Hi,

How many maximum number of verbs that can be used consecutively after the subject of a sentence?

Thanks

[Cerberus™]

There is no maximum, in theory: I would have asked mother to tell father to approach the mayor in order to beg him to have his assistant ask...

[David30]

Thanks Cerberus

[David30]

Is it compulsory to use a first form verb after a modal verb?

[Hamids]

yes, its called bare infinitive , in that case
you must not ear shoes while inside a mosque

[David30]

Thanks Hamids

[David30]

Modal Auxiliary Verb + have / have been + 2ndform / present participle.

Is it correct ?