The copula "be", along with the modal verbs and the other auxiliaries, form a distinct class, sometimes called "special verbs" or simply "auxiliaries". These have different syntax from ordinary lexical verbs, especially in that they make their interrogative forms by plain inversion with the subject, and their negative forms by adding "not" after the verb ("could I ...? I could not ..."). Apart from those already mentioned, this class may also include "used to" (although the forms "did he use to?" and "he didn't use to" are also found), and sometimes "have" even when not an auxiliary (forms like "have you a sister?" and "he hadn't a clue" are possible, though becoming less common). It also includes the auxiliary "do" ("does", "did"); this is used with the basic infinitive of other verbs (those not belonging to the "special verbs" class) to make their question and negation forms, as well as emphatic forms ("do I like you?"; "he doesn't speak English"; "we did close the fridge"). For more details of this, see "do"-support.