syllable structure (to avoid uncomfortable consonant clusters), whereas the variant -re is used only in a few frequent comparatives. In many cases, especially in longer words and words of a Latin or Greek origin, the comparative and superlative are formed with the adverbs mere and mest instead: e.g. intelligent, mere intelligent, mest intelligent. The comparative is inflexible, and it is not used with the definite article (in which case Danish uses the superlative instead). The conjunction of comparison is end, "than". The superlative is inflected like the positive (the t-form being identical to the n-form); længst, længste. When used as a predicate, the basic form is used instead of the e-form: hans ben er længst "his legs are the longest". And since a superlative used attributively must necessarily modify something definite, the e-form is always used there: den vredeste killing er vredest "the angriest kitty is angriest". Irregularities The inflection of some adjectives is irregular: Ny (new) and fri (free) take -t and optionally -e, even though they end in vowels. Several common adjectives with the suffix -s (historically the ending of the genitive) are inflexible, e.g. fælles, "common" (: fælle, "fellow"); ens, "identical" (: en "one"); træls, "annoying" (: træl, "slave") (one also hears trælst, trælse). Adjectives with the very common -sk ending are special. If they are polysyllabic or refer to a country, geographic area or ethnic group, they never take -t. Et klassisk stykke (a classical piece), et svensk hus (a Swedish house). Otherwise the -t is optional. Et friskt pust, or et frisk pust (a breath of fresh air). Some words never take the t-ending: stems ending in another -t (e.g. mat, "weak"; sort, "black") stems ending in -et (-ed) (e.g. tobenet, "biped"; elsket, "loved"; fremmed, "foreign"). This is also the case with the word glad "happy". The t-form sometimes undergoes phonetical changes that are not reflected orthographically, especially shortening of the preceding vowel or assimilation of a preceding consonant: e.g. god : godt ; ny : nyt ; syg : sygt (alternatively ). The adjectives ending in -en (originally past participles of the strong verbs) have either -ent or -et in the t-form: e.g. et sunke(n)t skib, "a sunken ship"; et give(n)t antal, "a given number" (the choice is often a matter of style or tradition). Adjectives in -vis have an optional -t in the t-form: et gradvis(t) salg, "a phased sale". Some adverbs may