Re: part of speech of "be going to"
That's one way of looking at it. Another is to consider it as the present progressive (first person singular) of the verb GO followed by an infinitive particle and the base form of the verb TIDY (or, if you prefer, the to- infinitive of the verb TIDY).
Originally Posted by hela
The present progressive of the verb GO is itself constructed with the auxiliary verb BE (first person singular) followed by the -ing form (present participle) of the verb GO.
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