Solution:
Here, the sentence talks about the 'house' as general class of things. Since we are referring to general things, we need to use the definite article 'a'.
44. He hopes to join . . . . . . . . university soon.
Solution:
'a' should be used before words with consonant sounds at the beginning and 'an' before words with vowel sounds at the beginning when talking about something general. The word 'University' has consonant sound 'yoo'. Hence, article 'a' is used.
45. In . . . . . . . . past, . . . . . . . . air pollution was generally considered basically . . . . . . . . urban phenomenon.
Solution:
The first blank shall take 'the' as the sentence talks about a specific time. The second blank won't take any article as 'air pollution' is uncountable. The third blank shall take 'an' as the following phrase 'urban phenomenon' is a singular countable noun and starts with the vowel 'u'.
46. . . . . . . . . MLA can help you in this regard.
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 MLA begins with 'em' and therefore 'an' article will be used.
47. His father works as . . . . . . . . electrician.
Solution:
'An' is indefinite article which is used before a word that begins with vowel sound and which refers to unspecific/general things. Here, 'electrician' begins with a vowel sound and it is unspecific.
48. Ganga is . . . . . . . . holiest river of India.