English Idiom — Choose the best substitute. Sentence: The time is running out; you must look sharp.

Introduction / Context:
“Look sharp” is a conversational British-English idiom meaning “hurry up,” “be quick,” or “move briskly.” It is often used to urge immediate action when a deadline is near. The preceding clause “The time is running out” strongly signals urgency, not caution or general prudence.

Given Data / Assumptions:

• Clue phrase: “time is running out.”
• Idiom: “look sharp.”
• Options: be careful, make haste, be punctual, be sensible.

Concept / Approach:
The best single-phrase substitute is “make haste,” which directly communicates the need to act quickly. “Be punctual” refers to being on time at a future point, while “be careful” emphasizes caution that could slow action. “Be sensible” focuses on judgment, not speed. Idioms must be interpreted in their pragmatic context; urgency is the key here.

Step-by-Step Solution:

Verification / Alternative check:
Paraphrase: “Time is running out; you must make haste.” This produces the same meaning and tone, frequently seen in exam directions and emergency instructions.

Why Other Options Are Wrong:

• be careful: Emphasizes safety, not speed.
• be punctual: Concerns scheduled arrival; not immediate acceleration.
• be sensible: About prudence; unrelated to quickness.

Common Pitfalls:
Equating “sharp” with intelligence. In this idiom, “sharp” refers to briskness or quick action, not cleverness.

Final Answer:
make haste