Meaning: The boy went to sleep, and he started to dream.
Choice of Words: Slept means that the boy was in a state of rest, dreams took flight means that the boy started to have dreams.
Alternative Expressions
The boy was sleeping, and his dreams were flying.
Meaning: This means the same thing as the first sentence, but it is written in a different way.
Choice of Words:The boy is a noun phrase that refers to a specific young male child. Was sleeping is a verb phrase that means to be in a state of sleep. And is a conjunction that connects two clauses. His dreams are noun phrase that refers to the thoughts and images that occur in the boy's mind during sleep. Were flying is a verb phrase that means to move or travel through the air. When you put them together, "The boy was sleeping, and his dreams were flying" is a sentence that describes a boy who is sleeping and dreaming.
As the boy slept, his dreams soared through the night sky.
Meaning: This means the same thing as the first two sentences, but it is written in a more poetic way.
Choice of Words:As is a conjunction that introduces a dependent clause. The boy slept is a dependent clause that describes the boy's state of being. His dreams are noun phrase that refers to the thoughts and images that occur in the boy's mind during sleep. Soared is a verb that means to fly or rise high in the air. Through is a preposition that means to move or pass from one place to another. The night sky is a noun phrase that refers to the sky at night. When you put them together, "As the boy slept, his dreams soared through the night sky" is a sentence that describes a boy who is sleeping and dreaming, and his dreams are flying high in the sky.