0 a layer of air containing ozone high above the earth that prevents harmful ultraviolet light from the sun from reaching the earth --
1 a layer of ozone (= a form of oxygen) above the earth that protects the earth from the sun’s ultraviolet light --
2 a layer of air high above the Earth that contains ozone (= a form of oxygen) and that prevents harmful light from the sun from reaching the Earth --
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.