【正确答案】 Life contains neither unalloyed happiness nor mere misery. Happiness and misery beget, complement and set off each other.
Happiness is a wisp of fleecy cloud: misery a mass of threatening dark cloud. These different clouds overlap on the horizon of your life to create a beautiful dusk for you when "the setting sun is most lovely indeed".
An individual's life must inevitably reach the point when "dusk is so near", and the rosy sunset cloud may make one nostalgic and melancholy. But human life goes on and on. The Earth ceaselessly rotates on its axis around the sun. When it is dark in the east, it is light in the west.