In the following question, select the option that best explains the information conveyed in the sentence.  He was building a castle in the air.

Step 1: Analyze the question The sentence "He was building a castle in the air" uses an idiom. We are asked to choose the option that best explains its meaning, so we must look past the literal words.

Step 2: Explain the concept "To build castles in the air" (also "castles in Spain") means to daydream or make grand plans that are unrealistic and unlikely to happen. It describes someone who imagines a wonderful future but has no practical basis for achieving it.

Step 3: Evaluate the options

• A. He was building flying fortresses – This is a literal reading. The idiom is figurative, so it is wrong.
• B. He was imagining a terrible future – The idiom is about pleasant dreams, not fears or negative outcomes, so it is wrong.
• C. He was imagining a possible future as a famous architect – The word "castle" is a distraction here. The idiom has nothing to do with architecture, and "possible" contradicts the idea of something unrealistic. It is wrong.
• D. He was imagining a wonderful and rather impossible future – This matches the idiom. "Wonderful" fits the grand dream, and "rather impossible" fits its unrealistic nature. It is correct.

Step 4: Answer

Exam tip: When you see an idiom, never take the words literally. Ask yourself, "What is the general feeling?" A "castle in the air" is a dream with no foundation, and a building with no foundation cannot stand. Also watch for distractor words like "castle" that tempt you toward options about buildings or architects.