A boat or something is missing.

The brisk boat drifted away. Lightness means effortlessness and relaxation. Gradually means increasing or decreasing the degree or quantity bit by bit. Then the canoe drifted away, indicating that a light-looking ship was getting farther and farther away.

When writing extended sentences, we should first understand that the purpose of extended sentences is to fill in appropriate additional components before and after the main components of the sentence and modify them to make the sentence more complete, concrete and vivid.

Generally, the words to be filled in are modifiers, which include adjectives and adverbs. Adjectives, such as Snow White, are used before nouns. Adverb: ... (ground), such as happily, used before verbs. Then when expanding sentences, we should choose adjectives or adverbs according to the situation, and usually accumulate more modifiers, so it will be easier when expanding sentences.