[Dr. Jamshid Ibrahim]

Originally Posted by kirimaru

I'm using a text book named A University Grammar of English ,an interesting but difficult one .In the chapter about verbs & the verb phrase ,I find the classification of verbs :
verbs consist of two kinds,lexical verbs & auxiliary .Modal auxiliaries include can ,may shall ,will ,could ,might ,should,would,must,ought to,used to ,need,dare

what's about have to ? Is have to a modal verb?
If it is a modal verb ,why isn't it mentioned in this part?
Please help me with this .

Modal verbs like: can, will, must are also called defective verbs because they don't have a past participle like will, can or even a past tense like must. Hence they cannot be used in perfect or future tenses. You need substitutes which make up for this deficiency like: have to and be able to.