Meaning: The clouds were moving slowly and smoothly across the blue sky.
Choice of Words: Clouds is a noun that refers to the visible masses of tiny water droplets or ice crystals suspended in the atmosphere. Drifted is the past tense of the verb to drift, which means to move slowly and smoothly in the air or water. Slow is an adverb that describes the speed at which the clouds were moving. Blue is an adjective that describes the color of the sky. Sky is a noun that refers to the expanse of air and space above the earth.