Step 1: Understanding the Concept:
This problem requires converting an imperative sentence from direct speech into indirect speech. Imperative sentences express commands, requests, or pieces of advice. When changing negative imperatives (sentences starting with "Do not") into reported speech, the reporting verb is adjusted to fit the mood, and the negative command transforms into an infinitive structure (not + to-infinitive).
Step 2: Detailed Explanation:
Let's analyze the steps required to convert the given direct statement:
1. Reporting Verb: The phrase "Do not waste your time" is a constructive suggestion or piece of guidance. Therefore, changing the reporting verb "said" to "advised" captures the contextual meaning perfectly.
2. Handling the Negative Imperative: The directive phrase "Do not waste" is converted into an infinitive structure by dropping "do" and formatting it as "not to waste".
3. Pronoun Shift: The generic possessive pronoun "your" shifts to align with the implied audience (us/our). Thus, "your time" transforms smoothly into "our time".
Let's review the options:
- Option (A) incorrectly leaves the words "do not" in place alongside the infinitive verb structure.
- Option (B) perfectly changes the format to "advised us", introduces the negative infinitive link "not to waste", and applies the correct pronoun shift ("our time").
- Option (C) incorrectly treats the phrase as a standard declarative clause by using "that we did not".
- Option (D) presents a structurally ungrammatical configuration ("ordered that do not").
Step 3: Final Answer:
The correct indirect speech form is: "The teacher advised us not to waste our time."