Hi, I would like to ask some questions about modal auxiliary.
First, does HAVE TO belong to MODAL AUXILIARY?
I have visited some websites on this topic. (I also searched here for the keyword, but there are too many articles and thus I couldn't read through them all.)
Some of them say it is a modal.
http://www.englishpage.com/modals/haveto.html
Some of them, however, say it is the auxiliary verb HAVE combined with an infinitive.
http://grammar.ccc.commnet.edu/grammar/auxiliary.htm
Furthermore, some say it is even not an auxiliary, but a main verb with an infinitive.
http://www.englishclub.com/grammar/verbs-modals-have-to-must-not-1.htm
I feel confused and would like to know which of the above statement is true. Or, which is more popular?
Second, how about HAD BETTER?
Third, it is OUGHT with an infinitive, or OUGHT TO with a bare infinitive?
The last, please tell me if I should add more words to the following.
Primary auxiliary verbs: be, do, have
Modal auxiliary verbs: can/could, may/might, shall/should, will/would, must/ought to, used to, need, dare
Thank you in advance for your help.