0 an isotope of hydrogen that is twice the mass of ordinary hydrogen: --
1 a type of hydrogen (= gas) that is twice as heavy as the usual form of hydrogen --
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.