The correct answer is option 2 i.e. had known.

Explanation   

'Would have' is used in conditionals to talk about something that did not happen in the past. ​The given sentence is a third conditional.

• ​Note that when using the third conditional, 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.
• Only option 2 uses 'had'+ past participle form of the verb i.e. known.

• Third conditional sentences are used to explain that present circumstances would be different if something different had happened in the past. Eg - If you had told me you needed a ride, I would have left earlier. 
• These sentences express a condition that was likely enough, but did not actually happen in the past. The speaker in the given example was capable of leaving early, but did not.

The correct answer is option 3 i.e. hardest.

Explanation 

There are three degrees of adjectives-

• Positive degree- It is the base form of the adjective.
  • Eg- He is very old.
• Comparative degree- It is used while making a comparison between two things or people.
  • Eg- He is older than me.
• Superlative degree- It is used while making a comparison of one thing with many other things or while expressing a thing of the highest intensity.
  • Eg- I am the oldest in my family.
• Clearly, the given sentence comparing the last part of the book with its other parts. A superlative adjective should be used here.
• Hence, among the options 'hardest' is the most appropriate answer.

The three forms of the adjective 'hard' are- hard, harder, and hardest. 'Most hardest' is not an appropriate form and is not generally used.

The correct answer is option 2 i.e. compact.

Explanation         

Let us find the relation between the first two words-​ 

• Big and enormous are both synonyms.
• Now we need to find a word which is the synonym of 'small'.
  • Compact means having all the necessary components or features neatly fitted into a small space.
  • Tidy means arranged neatly and in order.
  • Stubborn means having or showing dogged determination not to change one's attitude or position on something, especially in spite of good arguments or reasons to do so.
  • Insufficient means not enough; inadequate.

Clearly, 'compact' is the correct word.

Synonyms are words or phrases that means exactly or nearly the same as another word or phrase in the same language.

‘whether’ is a conjunction that expresses a doubt or choice between alternatives.

It is used before the alternatives being discussed, and the alternatives are separated by ‘or’. Since the pronoun ‘they’ is used it denotes that subject (i.e. ‘thing) must be plural.

Thus, option 2 is the correct answer.

The correct answer is option 3 i.e. spontaneous.

Explanation      

In the given sentence, 'but' is used which means that the required word must be opposite in meaning to 'decided beforehand'. Let us look at the meanings of the options-

• Speedy means did or occurring quickly.
• Sporadic means occurring at irregular intervals or only in a few places; scattered or isolated.
• Spontaneous means happening or done in a natural, often sudden way, without any planning or without being forced.
• Sponsered means provide funds for (a project or activity or the person carrying it out).

Clearly, 'spontaneous' is the correct word.

'But' is a conjunction that is used to introduce a statement that is contradictory to what has already been said.

• Eg- She was rich but rude.

The correct answer is option 4.

Explanation  

Let us look at the meanings of the words in each of the options-

• Distant means far away in space or time.
• Remote means situated far from the main centres of population; distant.
• Viable means capable of working successfully; feasible.
• Feasible means possible to do easily or conveniently.
• Trite means lacking originality or freshness; dull on account of overuse.
• Cliched means showing a lack of originality; based on frequently repeated phrases or opinions.
• Brevity means concise and exact use of words in writing or speech.
• Verbosity means the fact or quality of using more words than needed; wordiness.

​
Clearly, the words in option 4 are opposite to each other.

The correct answer is option 1.

Explanation         

The first blank requires a verb. The second blank requires a preposition.

• Buy is a verb which means 'to get something in exchange for money'.
• By is a preposition indicating the location of a physical object beside a place or object.
• 'Buys' is third person singular present.
  • ​I buys vegetables.            
  • She buys vegetables.               
• 'Bye' is short for 'goodbye'.

Clearly, only option 1 is correct.

Homophones are words that have a different spelling, different meaning but the same pronunciation.  Eg- buy and by.

Verbs are called action words.

Prepositions are words governing, and usually preceding, a noun or pronoun and expressing a relation to another word or element in the clause.

In the sentence a word that is complementary to 'freedom' is required. Hence, 'piece' which means a portion can be eliminated. This leaves us with options 2 and 3. It can be gathered from the sentence that invasion resulted in violence and hardships though it promised positive things like democracy, peace and freedom. So all these promises were false ideas. Thus, 'illusion' best fits here, making option 2 the correct answer.

An 'allusion' is an indirect or passing reference.
E.G. The Renaissance writers alluded to literature written during the Classical Greek period.

The correct answer is option 2 i.e. lenient.

Explanation      

Stringent means are strict, precise, and exacting.
Let us look at the meanings of the options-

• Fatal means causing death.
• Lenient means more merciful or tolerant than expected.
• Grave means giving cause for alarm; serious.
• Dire means extremely serious or urgent.

Clearly, 'lenient' is the correct word.