A.I. Explanation:

Correct answer: When

Explanation: The word 'When' indicates a specific time frame in which the events occurred, aligning perfectly with the context of the sentence that describes a past event. It connects the joining of the World Trade Organization with the subsequent economic changes, making it grammatically and contextually appropriate.

Meaning: 'When' refers to the time at which something happens, indicating that the events of dropping tariffs and growing richer occurred at the same time as China's joining the WTO.

Wrong options:

• Until: 'Until' suggests a condition that continues up to a certain point, which does not fit the context of describing simultaneous events.
• Unless: 'Unless' implies a condition that must be met for something to happen, which is not relevant here as the sentence describes a factual occurrence.
• As if: 'As if' introduces a hypothetical situation, which does not match the factual nature of the events being described.

Correct answer: will find

Explanation: The phrase 'will find' is in the future tense, which is appropriate here as it refers to an event that will happen when the Olympic Games occur. This aligns with the context of the sentence, which discusses a future event.

Meaning: 'Will find' means that in the future, people will discover or experience something, in this case, the transformation of the city and country.

Wrong options:

• would find: 'Would find' suggests a conditional situation rather than a definite future occurrence, making it less suitable in this context.
• finds: 'Finds' is present tense and does not match the future context of the sentence.
• has found: 'Has found' is present perfect tense, which indicates a completed action that does not fit the future context of the sentence.

Correct answer: one of

Explanation: The phrase 'one of' indicates that China is part of a larger group, specifically the largest economies in the world. This fits grammatically and contextually as it describes China's status among other economies.

Meaning: 'One of' means that China is included in a group of the largest economies, highlighting its significance.

Wrong options:

• any of: 'Any of' implies a selection from a group without specificity, which does not convey the intended meaning of being part of the largest economies.
• almost: 'Almost' suggests proximity to a condition but does not indicate membership in a group, making it unsuitable here.
• either: 'Either' is used to indicate a choice between two options, which does not apply to the context of describing China's economic status.

Correct answer: significat

Explanation: The word 'significat' (likely a typo for 'significant') describes the importance of China's role as a trading partner. It fits grammatically as an adjective modifying 'trading partner' and contextually as it emphasizes China's growing influence.

Meaning: 'Significat' means important or noteworthy, indicating that China is a crucial trading partner for the US.

Wrong options:

• particular: 'Particular' suggests specificity but does not convey the importance of the trading relationship, making it less fitting.
• self-conscious: 'Self-conscious' refers to being overly aware of oneself, which is irrelevant in this context about trade relations.
• narrow-minded: 'Narrow-minded' implies a lack of openness, which contradicts the positive context of China's role as a trading partner.

Correct answer: of

Explanation: The preposition 'of' indicates a relationship between China and the US, specifically that China is a trading partner belonging to or associated with the US. This fits grammatically and contextually within the sentence.

Meaning: 'Of' denotes belonging or association, indicating that China is a trading partner for the US.

Wrong options:

• by: 'By' suggests agency or means, which does not fit the context of describing a relationship between China and the US.
• to: 'To' implies direction or destination, which is not appropriate in this context of partnership.
• from: 'From' indicates origin, which does not convey the intended meaning of partnership in trade.