Solution:
In the first blank, article "a" will be used because here pity is being used in the general sense (a cause for regret or disappointments) and it is considered to be countable (general) noun. In the second blank, article "a" will be used because 'year' is a common noun and has a consonant sound.

Solution:
Here, the sentence talks about the 'time' as general class of things. Since we are referring to general things, we need to use the definite article 'a'.

Solution:
In the first blank, article "the" will be used because the speaker is mentioning some specific place. In the second blank, article "the" will be used because article 'the' is used with something unique (The Sun, The Moon).

Solution:
Use 'an' before words such as "hour" 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". Here X-ray begins with 'ex' and therefore 'an' article will be used.

Solution:
Use 'an' before words such as "hour" 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:
Here, 'zoo' is a common noun and indefinite article will be used. Hence, 'a' is the correct answer as 'zoo' starts with a consonant sound.

Solution:
Option C is correct as 'The' is used with words with superlatives. 'Tallest' is superlative.