II. Put in the article the where necessary: 1. .... National Gallery is in ... Trafalgar Square. 2. .... Heathrow is the largest airport in ... London. 3. .... Tower of London stands by ... River Thames. 4. .... Washington is the capital of ... USA. 5. .... Plaza Hotel which is in ... Park Street.

Solution:

1. The National Gallery is in Trafalgar Square.
2. Heathrow is the largest airport in London.
3. The Tower of London stands by the River Thames.
4. Washington is the capital of the USA.
5. The Plaza Hotel which is in Park Street.

Explanation:

• We use 'the' before unique entities like 'The National Gallery', 'The Tower of London', 'the USA' (as a specific entity representing the country), and when referring to a specific river like 'the River Thames'.
• 'Heathrow' and 'London' are proper nouns for which 'the' is not typically used in this context.
• 'Park Street' is a specific street name, and usually, 'the' is not used before street names unless it's part of a larger, specific landmark or a generic statement about streets in general. In this case, 'Plaza Hotel' is a specific building, so 'The' is used before it.