The best word to fill in the gap in the sentence;You should not sleep ________ day is; By.
The use of By in a Sentence
The word 'by' can be an adverb, a noun, an adjective, a preposition or an interjection.
The adverbial use of the word by in the sentence as given is used to indicate when the individual should sleep.
Read more on adverbs;
https://brainly.com/question/13973406
