Necessity, constructions with KERAK

The main construction for necessity, "verb-ISHI KERAK", is formed with the infinitive of the verb suffixed by the personal type of personal suffixes, followed by the nominal predicate kerak, at an impersonal form (third person singular, no marking), which follows in turn the various patterns used for conjugating stative constructions.

With the verb kelmoq, 'to come':

kelishim kerakI must come
kelishing kerakYou must come
kelishi kerakHe/she must come
kelishimiz kerakWe must come
kelishingiz kerakYou must come
kelishlari / kelishi kerakThey must come

A first negative is formed by adding emas to the nominal predicate kerak. It means that the state or action is not necessary.
A second negative is formed by adding -maslik to the verbal stem, then followed by the personal suffix, and then by kerak. It means that it is necessary that the state or action does not occur.
The past stative is formed by adding edi to the nominal predicate kerak.
The stative inferential is formed by adding ekan to the nominal predicate kerak.
The reported stative is formed by adding emish to the nominal predicate kerak.

kelishi kerak emasHe/she has not to come (it is not necessary for him/her to come)
kelmasligi kerakHe/she must not come (it is necessary that he/she does not come)
kelishi kerak ediHe/she had to come
kelishi kerak ekan(It looks like) he/she must come
kelishi kerak emishApparently he/she must come

For other tenses or aspects, constructions with the verb bo'l-, 'to be, become' are used.
For instance:

kelishi kerak bo'lgan ediHe/she had had to come
kelishi kerak bo'lsaIf he/she must come