0 feeling doubt; uncertain what to think, expect etc -- nejistý, pochybovačný
1 able to be doubted; not clear -- pochybný; nejasný
2 uncertain but rather unlikely, unhopeful etc -- nejistý, neurčitý, pochybný
It is doubtful whether this will work
a doubtful improvement.
3 suspicious -- pochybný
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.
Můžeme to dokončit krok za krokem, ať je cesta jakkoli dlouhá, a nelze ji dokončit, ať je cesta jakkoli krátká, pokud si ani neoznačíte svou stopu.