difficult / hard, probably impossible

prediction

predict

economics; the study of economics / economy

up and down, the upper and the lower / outerwear and underwear / the nobility and the commoners

up and down / high grade and low grade / the upper and lower houses of the Diet or parliament / ascending and descending, climbing up and climbing down

ascending and descending, ascent and descent

to ascend and descend, to go up and go down

rise and fall, fluctuation (as a level of something, such as a price)

to rise and fall, to fluctuate (as a level of something, such as a price)