A.I. Explanation:

Correct answer: making

Explanation: 'Making' is the correct choice as it fits grammatically in the context of the sentence, indicating the action of improving older buildings. It aligns with the focus on enhancing energy efficiency, which is the main topic of the sentence.

Meaning: 'Making' means to create or cause something to happen, in this case, improving the energy efficiency of buildings.

Wrong options:

• building: 'Building' refers to the act of constructing something new, which does not fit the context of improving existing structures.
• taking: 'Taking' implies receiving or acquiring, which does not convey the intended action of enhancing buildings.
• hiring: 'Hiring' means to employ someone for a job, which is unrelated to the context of modifying buildings for energy efficiency.

Correct answer: meeting

Explanation: 'Meeting' is the appropriate choice as it indicates the act of fulfilling or satisfying today's environmental standards, which is the intended meaning in the context of the sentence.

Meaning: 'Meeting' means to satisfy or comply with a requirement or standard, in this case, environmental standards.

Wrong options:

• searching: 'Searching' implies looking for something, which does not fit the context of fulfilling standards.
• starting: 'Starting' suggests beginning something, which does not align with the idea of complying with established standards.
• investing: 'Investing' refers to allocating resources for future benefits, which does not convey the action of fulfilling standards.

Correct answer: without

Explanation: 'Without' is the correct choice as it indicates the condition of achieving something in the absence of compromising historical integrity, fitting grammatically and contextually into the sentence.

Meaning: 'Without' means in the absence of or not having something, here referring to not compromising integrity.

Wrong options:

• by: 'By' indicates the means or method of doing something, which does not fit the context of avoiding compromise.
• due to: 'Due to' suggests a cause or reason, which does not align with the intended meaning of avoiding compromise.
• under: 'Under' implies a condition or state, which does not convey the intended meaning of not compromising integrity.

Correct answer: blend

Explanation: 'Blend' is the correct answer as it indicates the action of combining the new with the old, which is the focus of urban planning in the context of the sentence.

Meaning: 'Blend' means to mix or combine different elements together, in this case, new developments with historical architecture.

Wrong options:

• commoditize: 'Commoditize' means to turn something into a commodity, which does not fit the context of integrating new and old.
• orient: 'Orient' refers to positioning or aligning something, which does not convey the idea of combining elements.
• network: 'Network' implies creating a system of connections, which is unrelated to the idea of blending new and old architectural styles.