0 used to show that it is necessary or very important that something happens in the present or future: --
Meat must be cooked thoroughly.
I must get some sleep.
Luggage must not be left unattended (= it is against the rules).
formal "Must I sign this?" "Yes, you must."
I must say, you look absolutely great.
1 used to show that something is very likely, probable, or certain to be true: --
2 something that is necessary: --
3 something that is so good, you must do it, have it, or see it: --
It's a moderately entertaining film but it's certainly not a must-see.
4 used to show that it is necessary or important that something happen in the present or future: --
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
Можем да го завършим стъпка по стъпка, колкото и дълъг да е пътят и не може да бъде завършен, колкото и кратък да е пътят, ако дори не маркирате отпечатъка си.