By English grammar, Modal verbs

i need to know where can i find english grammar rules! i shoudl write a work "modal verbs: can & may in the function of permission"!!!)

Hi Miriam, Actually "had better" is NOT a modal verb. Some authors call it a "modal idiom" (The New Fowler's Modern English Usage edited by R.W. Burchfield), or a idiomatic modal. There are many English Grammar websites that talk about "had better" as a Modal Verb. For...