A.I. Explanation:

Question Focus: Labeling the outer, non-moving part of the lock in the diagram

Correct Answer: housing

Passage Reference: Its main components are the housing (the outer part of the lock which does not move

Why this is correct: In the diagram, this label points to the outer part of the lock that does not move. The passage clearly defines this as the housing, so copying that exact word is correct.

Common Mistake: Students sometimes write outer part because that is how it is described, but the diagram answer must use the exact word from the passage. Writing a description instead of the passage word is a synonym trap.

Paraphrasing: Passage: 'the housing (the outer part of the lock which does not move)' = Diagram: 'outer fixed part of the lock'

Tips: For diagram questions, look for definitions in brackets - they often match the diagram labels.

Key Vocabulary:

• housing = outer cover
• mechanism = moving system

Question Focus: Identifying the vertical metal parts inside the shafts

Correct Answer: pins

Passage Reference: Inside these shafts are pairs of metal pins of varying length, held in position by small springs.

Why this is correct: The diagram arrow points to the small vertical metal pieces inside the lock. The passage names these clearly as pins, so that is the correct label.

Common Mistake: Some students write shafts because the pins sit inside them, but the arrow points to the metal pieces themselves, not the holes. This is a context shift trap.

Paraphrasing: Passage: 'pairs of metal pins' = Diagram: 'small vertical metal parts'

Tips: Check carefully what the arrow touches - the object itself, not the space around it.

Key Vocabulary:

• shaft = narrow hole
• pin = small metal rod

Question Focus: Labeling the parts that hold the pins in position

Correct Answer: springs

Passage Reference: Inside these shafts are pairs of metal pins of varying length, held in position by small springs.

Why this is correct: The diagram shows small coiled parts above the pins. The passage says the pins are held in position by small springs, so the correct label is springs.

Common Mistake: Students sometimes write coils based on the picture, but that word does not appear in the passage. This is a synonym trap.

Paraphrasing: Passage: 'small springs' = Diagram: 'coiled parts above the pins'

Tips: Even if the picture suggests another word, always copy the exact word from the passage.

Key Vocabulary:

• spring = elastic metal coil
• position = place

Question Focus: Identifying the object inserted into the lock

Correct Answer: key

Passage Reference: When you put the correct key into the cylinde

Why this is correct: The diagram shows the object being inserted into the lock from outside. The passage clearly calls this the key, so that is the correct answer.

Common Mistake: Some students write correct key, but the diagram label only needs the object name. Adding extra words is unnecessary and risks a word limit trap.

Paraphrasing: Passage: 'put the correct key into the cylinder' = Diagram: 'object inserted into the lock'

Tips: Use the shortest correct form when labeling diagrams unless the passage requires more words.

Key Vocabulary:

• key = metal opener
• insert = put in

Question Focus: Labeling the central rotating part of the lock

Correct Answer: cylinder

Passage Reference: Its main components are the housing (the outer part of the lock which does not move), the central cylinde

Why this is correct: The arrow points to the central round part that turns when the key is used. The passage names this part the cylinder, so that is the correct label.

Common Mistake: Students sometimes write mechanism, but the mechanism is a different part connected to the cylinder. This is a partial truth trap.

Paraphrasing: Passage: 'the central cylinder' = Diagram: 'middle turning part of the lock'

Tips: If the passage lists components, those exact nouns are very often used as diagram answers.

Key Vocabulary:

• cylinder = round central part
• rotate = turn

General Tips:

• Diagram completion answers always come directly from the passage - never invent your own words.
• Follow passage order - later labels usually appear later in the text.
• Check the word limit carefully. Short labels are safest.
• Look at what the arrow touches, not just what is nearby.