In this passage completion question about a kerosene pump stove, choose the correct preposition to fill the blank in the phrase: the fuel in the tank below would be ________ pressure.

Introduction / Context:
Passage completion questions test your understanding of natural English collocations and how different prepositions convey specific meanings in context. The passage here describes how a kerosene pump stove works. It mentions that when the kerosene burned, the fuel in the tank below would be something pressure. In physics and everyday English, there is a very common collocation that describes a substance being subjected to pressure.

Given Data / Assumptions:

• The relevant fragment of the passage is: the fuel in the tank below would be ________ pressure.
• The options are inside, into, about, under.
• The sentence describes the physical state of the fuel when the stove is operating.
• The correct choice should form a natural and meaningful phrase used in standard English.

Concept / Approach:
In English, the usual phrase for describing a substance subjected to pressure is under pressure. This expression is widely used in both scientific and everyday language, for example gas under pressure or a system under pressure. The preposition under conveys the idea of an external force acting on something. None of the other options forms a standard collocation with pressure here, so under is the best fit. Recognising such fixed phrases is essential in passage based questions.

Step-by-Step Solution:
Step 1: Read the sentence with each option inserted: inside pressure, into pressure, about pressure, under pressure.Step 2: Evaluate which version sounds like a familiar and correct English phrase.Step 3: Inside pressure does not make sense, because inside describes location rather than the state of being subjected to pressure.Step 4: Into pressure is not idiomatic in this context, since into usually indicates movement from outside to inside, which is not the intended meaning.Step 5: About pressure also fails, because about suggests concerning or approximately, not a physical condition.Step 6: Under pressure is a standard phrase describing a fluid or object experiencing pressure, so this fits perfectly.

Verification / Alternative Check:
You can verify the answer by thinking of similar sentences from science class or technical manuals, such as The gas in the cylinder is under pressure or The boiler operates under high pressure. These examples confirm that under pressure is the normal and expected collocation. Replacing under with any of the other prepositions would make these sentences incorrect or awkward, which supports our selection for the exam sentence as well.

Why Other Options Are Wrong:
Inside suggests being located within something, not being subjected to a force, so inside pressure fails to convey the intended idea. Into indicates direction or movement and does not work with pressure in this stationary description. About is used for topics, approximations, or positions, which have nothing to do with the physical state of the fuel in the tank. Therefore none of these alternatives matches the clear and accurate phrase under pressure.

Common Pitfalls:
A common mistake in preposition questions is to focus only on literal meanings and ignore established collocations. Learners may overthink inside, imagining the pressure is inside the tank, or into, thinking about the fuel moving. However, the passage emphasises the condition of the fuel, not its location or direction. Remember that English often uses fixed word combinations, and knowing expressions like under pressure will help you answer rapidly and confidently in such questions.

Final Answer:
The correct phrase is: the fuel in the tank below would be under pressure.