Meaning: 'Being created' refers to the process of barricades coming into existence, emphasizing that the boulevards were built to stop this from happening.

Wrong options:

• been created: 'Been created' is the past participle form and does not fit the continuous aspect required in this context.
• created: 'Created' is a simple past form, which does not convey the ongoing nature of the action that was being prevented.
• have created: 'Have created' suggests a completed action in the present perfect tense, which is not suitable for the passive construction needed here.

Correct answer: part

Explanation: The word 'part' fits grammatically as it indicates a portion of something, which is appropriate in the context of describing the maze-like structure of earlier Paris. It aligns with the phrase 'in part,' which is a common expression used to indicate a contributing factor.

Meaning: 'Part' means a section or portion of something, indicating that the maze was a significant aspect of the earlier layout of Paris.

Wrong options:

• practice: 'Practice' refers to the act of doing something regularly and does not fit the context of describing a physical layout.
• pair: 'Pair' implies two items and does not relate to the singular concept of a maze or layout.
• pride: 'Pride' refers to a feeling of satisfaction and does not fit the context of describing the structure of streets.

Correct answer: simply

Explanation: The adverb 'simply' fits grammatically as it modifies the verb 'razed,' indicating the straightforwardness of the action. It conveys that the houses were destroyed without any additional complexity, which aligns with the context of the sentence.

Meaning: 'Simply' means in a straightforward or uncomplicated manner, emphasizing the directness of the destruction of the houses.

Wrong options:

• really: 'Really' is used to emphasize truth but does not convey the intended meaning of straightforwardness in this context.
• fully: 'Fully' implies completeness, which does not accurately describe the manner in which the houses were razed.
• basically: 'Basically' suggests a fundamental aspect but does not fit the context of describing the manner of destruction.

Correct answer: down

Explanation: The word 'down' fits grammatically as it is commonly used with 'torn' to indicate the action of demolishing buildings. This collocation is standard in English, making it the most appropriate choice in this context.

Meaning: 'Down' in this context means to demolish or destroy something, particularly buildings, indicating the action of tearing them apart.

Wrong options:

• up: 'Up' does not fit with 'torn' as it suggests an opposite action of raising rather than demolishing.
• back: 'Back' does not collocate with 'torn' in this context and does not convey the intended meaning of destruction.
• now: 'Now' is a temporal adverb and does not fit grammatically or contextually with the action of tearing down buildings.