сравните сущ по образцу
germany \canada\ china (big)
germany is big , china is bigger, canada is the biggest
1.the volga\ the irtysh\ the thames (long) 
2. village\ city\ town (big)
3.train\ plane\ car (fast)
4.Japan\ Belgium\ Spain (small)

Irtysh is long, thames is longger, volga is longestVillage is big, town is bigger, city biggestCar is fast, train is fasted, plane is fastestSpain is small, belgium is smaller, Japan is smallest