Let’s understand the meanings of the given words:

Illuminate = to light something and make it brighter

Decorate = to add something to an object or place, especially in order to make it more attractive

Pollute = contaminate (water, the air, etc.) with harmful or poisonous substances.

Colour = change the colour of (something) by painting, dyeing, or shading it.

• The sentence talks about the sky becoming bright due to the fireworks.
• So, the correct filler would be “illuminated”.

Hence,option Ais the correct answer.

The given sentence is in active form. The passive voice of imperative sentences which suggest order, suggestion or request can be made in two ways:

Active: Verb + object

Passive: 1. Let + object + be + past participle

2. You are requested/ordered/suggested + to + verb (Ist form) + object

So, with the help of the above structures, we can convert the sentence into passive voice: Let the New Year be celebrated with amazing offers.

Hence, option D is the correct answer.

The given sentence is in the active form. It is in the simple past tense.

The structures for active/passive voices are:

Active: Subject + verb (IInd form) + object...

Passive: Object + was/were + verb (IIIrd form) + by + subject...

So, with the help of the above structures, we can convert the given sentence into passive voice: My father built our home in 1990. 

Hence, option A is the correct answer.

The underlined part is grammatically incorrect.

• The given sentence is the case of the third conditional sentence.
• We use the past perfect (i.e., had + past participle) in the if-clause.
• The modal auxiliary (would, could, should, etc.) + have + past participle in the main clause expresses the theoretical situation that could have happened.
  Hence, replace "have" with "had".
• Also, "why" is used to ask "reasons" whereas "how" is used to emphasize something. In the given sentence, the person is focussing on the difficult part of getting a new job. Thus, "how" is appropriate here. 

Thus, the correct sentence will be:I would not have left my job if I had known how difficult it is to find another one.

Hence,option Cis the correct answer.

• Sentence C will be the first sentence as it introduces the theme of the passage i.e. ‘people complaining to wise man about the same problem’.
• Sentence B will come next as it mentions what happened when the wise man told a joke. 
• Next in the sequence will be D, as it tells us what happened when he repeated the joke.
• Sentence A aptly concludes the passage by giving the moral of the story.

Thus, the correct sequence will be:CBDA.

After rearranging the sentences, the passage will be: People came to the wise man to complain about the same problem every time. One day he told them a joke and everyone roared with laughter. When he repeated the joke twice, nobody laughed anymore. When we can’t laugh at the same joke again, why should we cry over the same problems?

Hence, option C is the correct answer.

• The blank needs a preposition that implies "occurring in or shared by some members of a group or community".  ‘Among’ means the same.
  e.g. Discuss it amongst yourselves and let me know your decision.
• Other prepositions and their meanings:
  About = on the subject of
  e.g. Let’s talk about something else.
  Along = from one end to or towards the other end of something
  e.g. I walked slowly along the road.
  Against = being an opponent to somebody/something in a game, competition, etc., or an enemy of somebody/something in a war or fight
  e.g. We played football against a school from another district.

Hence, option C is the correct answer.

• The sentence implies that Sun Yan, the deputy general-secretary of Beijing Racing Pigeons Association, conveyed that at least 100,000 pigeon breeders live in Beijing.
• Out of the given options, ‘said’ meaning "utter words so as to convey information, an opinion, a feeling or intention, or an instruction" is the apt word to fill in the blank.
• "Told" is followed by an object. And words like "advised" and "clarified" do not fit in the blank.

Hence, option A is the correct answer.

• We need a word to convey the message that nearly 90,000 people have registered themselves with the Racing Pigeons Associations.
• ‘Almost’ meaning ‘very nearly; not quite’ is the apt fit for the blank.
• The meaning of other words are:
  Exact = (completely) correct; accurate
  Nearby = not far away in distance
  Utmost = greatest
  Other words do not fit in the blank contextually.

Hence, option B is the correct answer.

• The blank needs an adjective to modify the noun ‘levels’.
• ‘Different’ meaning ‘not the same as another or each other; unlike in nature, form, or quality’ is the apt fit for the blank.
• Both "differ" and "differed" are verbs.
• Although "differential" can be used both as a noun and an adjective, it doesn't fit in the blank.

Hence, option A is the correct answer.

• The passage is about pigeons. Thus, we can easily eliminate "animal" and "cats".
• Between "bird" and "birds", "bird" is appropriate here as we need an adjective in the blank for the noun "owners".

Hence,option Dis the correct answer.