In the above sentence ‘couldn’t’ tells us that sentence is in the past tense so, instead of ‘will’, which is future tense, ‘would’ should come as it indicates the past tense. Hence, option B is the correct option.

The sentence is in the past tense and the later part of the sentence tells us that test must have been taken before and as its result the speaker got the passing grade. ‘After I took the test’ should come in the place of the underlined part because it is in past tense and ‘after’ tells us the action has been taken place whose result were “passing grades”. Hence, option A is the correct option.

The famous saying is “uneasy lies in the head that wears the crown”. It means that, A person who has great responsibilities, such as a king, is constantly worried and therefore doesn't sleep soundly. Here the ‘that’ is for the head and not for the person wearing the crown. The correct answer is option B.

'In' is used when referring to something that is done as a result of something else. Since the death of hundreds of people happened as a result of earthquake, we use 'in' instead of from. 'Because of' is used to introduce reason and is followed by a noun phrase or the ing form of the verb. The word earthquake is neither a noun phrase nor the ing form of the verb so we cannot use because of prior to it. 'Since' is used to refer to a point of time or from a definite past time until now.

In English language, each sentence must have a subject. If we do not have any subject, we use 'there' or 'it'. These are called dummy or empty subjects. We use a plural verb after 'there' to talk about a plural noun phrase and we use a singular verb with a singular noun phrase. 

In the bracketed part of the sentence, there is no subject before "being" due to which the sentence doesn’t make any sense. Therefore, the pronoun “it”, is required to correct the bracketed form. Hence, option (B) is the correct answer.

The sentence has a context of a present activity. It is an imperative sentence where some instructions or advice is being given. Moreover, the use of 'will' is incorrect since the subject has not been explicitly stated and an inference, here, makes the sentence grammatically incorrect. In imperative sentences, base verb is used which means option A is the correct answer.

There should be uniformity in the use of "no only but also". It means if "but also" is used before an object, then "not only" should also be used before the object. Similar is the case for verb too. Now, in the given sentence, the use of "not only" should be done before "giving hints". Thus, option B is the correct answer.

The adjective "accountable" is followed by preposition "to". So, no improvement is required in the sentence.

Habituated means make or become accustomed or used to something. 

Prepared means make something ready for use or consideration.

"Used " means be familiar with any action or habit.

The use of gerund "preparing" gives us a hint that the correct verb would be "used to. If you are used to something, you are accustomed to it – you don’t find it unusual. If you get used to something or you are getting used to something you are becoming accustomed to it – it was strange, now it’s not so strange.

I’m getting used to driving on the right.

Both ‘be used to’ and ‘get used to’ are followed by a noun (or pronoun) or the gerund – the ‘ing’ form of a verb.

I can’t get used to getting up so early.

He’s not used to the weather here yet.

‘Be/get used to’ can be used with past, present and future tenses.

You might find it strange at first but you’ll soon get used to it.

He wasn’t used to the heat and he caught sunstroke.

When two singular nouns are joined by "neither ..... nor", it carries a singular verb. The sentence follows this rules correctly, so, no improvement is required.