Choose the correct sentence.

You will not pass unless you work hard. This sentence effectively conveys a conditional meaning, indicating that passing is dependent on the effort put into studying or working hard. The use of "unless" establishes a clear cause-and-effect relationship, where the action of working hard is necessary to achieve the desired outcome of passing.

In English grammar, "unless" is a conjunction that introduces a condition that must be met for something else to happen. In this case, the sentence states that without hard work, passing will not occur. This structure is commonly used in both spoken and written English to express conditions, making it easily understood by the reader or listener. The simplicity and clarity of the phrase ensure that the message is direct and unambiguous.

Examining the other options reveals common mistakes that can lead to confusion. For instance, the use of "will" in options A and B is incorrect because "unless" already sets a conditional framework that does not require "will" in the main clause. Additionally, option D is grammatically incomplete, lacking the auxiliary verb "will," which is necessary to maintain proper tense and structure in the sentence. Therefore, when tasked to choose the correct sentence, the clear and grammatically sound option is "You will not pass unless you work hard."