Solution:
Use 'an' before words such as "hour" or "honour" which sound like they start with a vowel even if the first letter is a consonant. Also use 'an' before letters and numbers which sound like they begin with a vowel, such as "F" or "8".

Solution:
Use 'an' before words such as "hour" or "honour" which sound like they start with a vowel even if the first letter is a consonant. Also use 'an' before letters and numbers which sound like they begin with a vowel, such as "F" or "8".

Solution:
The first and fourth blank will take no article as 'Summer' is a name of a season and 'very hot' is irrelevant. The second blank will take 'a' article as summer is mentioned as one of the seasons. The third blank will take 'the' article as it is specified 'summer of last year'.

Solution:
No article is used after name of a country or a city.

Solution:
When a noun's identity is not known, it's a non-specific noun, hence an indefinite article is used. Indefinite articles like 'a' or 'an' are used when the noun is not specific (indefinite). The noun 'policeman' is non-specific hence article 'a' is used because 'policeman' begins with consonant sound.

Solution:
The indefinite articles, 'a' and 'an' are used before an indefinite noun. In the given sentence, the noun which follows the blank is 'policeman'. It starts with a consonant sound (p). Hence, the appropriate article is 'a'.

Solution:
Here, a specific group of people 'Brave' is being talked about. 'The' article will be used.