Fill in the blank with the correct preposition in the sentence "Pour the juice _____ the glass."

Introduction / Context:
Preposition questions test correct usage in everyday situations. The sentence describes the act of transferring juice from a container into a glass. We must select the preposition that accurately shows movement from one place to another and results in the juice being inside the glass.

Given Data / Assumptions:

The base sentence is Pour the juice _____ the glass.

The action involves movement of liquid from one container to another.

We want to express movement toward an interior space.

The options are in, into, onto, on and within.

Standard English has specific preposition patterns with verbs like pour.

Concept / Approach:
In English, into is used to express movement from outside to inside, especially when something crosses a boundary and ends up within a container or enclosed space. The preposition in typically indicates position, not movement. With the verb pour, the usual pattern is pour something into a glass, bottle or cup. Therefore, into is the correct choice for this sentence.

Step-by-Step Solution:
Step 1: Replace the blank with into. The sentence becomes Pour the juice into the glass, which clearly expresses the movement of juice into the glass. Step 2: Test in. Pour the juice in the glass may sometimes be heard, but it can also be interpreted as pour the juice while you are in the glass, and is not as precise in formal English. Step 3: Test onto. Pour the juice onto the glass suggests pouring on the outer surface of the glass, which is not what we want. Step 4: Test on. Pour the juice on the glass again suggests pouring on the outside, not inside. Step 5: Test within. Pour the juice within the glass sounds archaic and is not the normal modern collocation.

Verification / Alternative check:
Think of similar sentences: pour milk into the cup, pour water into the bottle, pour tea into the mug. All use into with containers. Replace juice and glass with other objects; the pattern still remains pour something into something, confirming that into is the standard preposition. Grammatically, into clearly marks direction and movement toward the interior, which is exactly what is intended.

Why Other Options Are Wrong:
In can indicate location and is sometimes used in casual speech but does not clearly emphasise the movement into the container. Onto and on indicate contact with a surface, not movement inside a container. Within is used to mean inside something but is normally not used directly after pour in this context.

Common Pitfalls:
Learners sometimes confuse in and into because both involve the idea of inside. The key difference is that in describes state, while into describes movement. Remember to use into after verbs that involve movement from one place to another, such as go, jump, throw and pour, when the destination is an interior space.

Final Answer:
The correct preposition is into, so the sentence should read Pour the juice into the glass.