The sentence given has a blank that must be filled with an appropriate phrasal verb. Choose the correct alternative: "The clock has __________ for want of winding."

Introduction / Context:
This question tests your knowledge of phrasal verbs and fixed expressions in English. It describes a mechanical clock that has stopped working because it has not been wound. In older mechanical clocks, failure to wind them regularly causes them to slow and eventually stop. The correct phrasal verb must reflect this idea of losing power and stopping due to a lack of energy or winding.

Given Data / Assumptions:

• Sentence: "The clock has __________ for want of winding."
• Options: run down, run short, run past, run up.
• "For want of winding" means "because it has not been wound".
• We assume a traditional mechanical clock that requires regular winding to keep working.

Concept / Approach:
The phrasal verb "run down" is commonly used for batteries, machines and clocks to mean losing power or stopping because of insufficient energy: "The battery has run down." In the case of a mechanical clock, "run down" means that the spring's stored energy has been used up and the clock has stopped. Other phrasal verbs with "run" carry different meanings, such as becoming short of something, passing something, or accumulating something, none of which fits the context of a clock stopping.

Step-by-Step Solution:
Step 1: Understand the sentence meaning: because the clock has not been wound ("for want of winding"), it no longer works correctly. Step 2: Consider option "run down". This is used for clocks and batteries to mean they have used up their stored energy and are slowing or stopping. Step 3: Consider "run short". This phrasal verb is used with supplies like "run short of money" or "run short of time", not with machines themselves. Step 4: Consider "run past". This typically means to move beyond a point, as in "run past the gate", and does not describe a clock's condition. Step 5: Consider "run up". This usually means to accumulate (like "run up a bill") or move quickly upwards; it does not fit the context of a clock lacking winding. Step 6: Recognise that only "run down" correctly describes what happens to a clock when it is not wound. Step 7: Conclude that "run down" is the correct phrasal verb to complete the sentence.

Verification / Alternative check:
Insert "run down" into the sentence: "The clock has run down for want of winding." This is a standard, idiomatic expression. Many older textbooks and exam papers use similar sentences to illustrate the phrasal verb "run down". No other option reads naturally or accurately describes a clock's condition. This confirms our choice.

Why Other Options Are Wrong:

• run short: Used with resources such as money or time ("We are running short of fuel"), not with devices themselves.
• run past: Describes motion beyond a point, not the state of a device lacking power.
• run up: Typically means accumulate (especially debts) or move upwards, which is unrelated to the idea of a clock slowing and stopping.

Common Pitfalls:
Because several phrasal verbs with "run" exist, students sometimes guess based only on partial familiarity, for example thinking of "run short" without realising it must be followed by "of something". To avoid such errors, always place the phrasal verb back into the sentence and check whether it makes full sense with all other words, especially the subject (here, "the clock") and the reason or result ("for want of winding").

Final Answer:
The correct completion is "run down", so the sentence reads: "The clock has run down for want of winding."