Correction

By indicates the means of achievement.

Children is plural and takes are. Its plural form is irregular.

The correct option avoids redundant intensifiers. Essential already conveys necessity.

After one of the, a plural noun is required, students. The superlative takes the.

Better is the comparative of good and is not preceded by more. Than, not then, is used in comparisons.

One agrees to a proposal or plan. Agree with is used with a person.

When comparing two, the comparative with the is used, the taller. The superlative is for three or more.

The third-person singular in the simple present takes goes. The habitual every day signals this tense.

For is used with a duration such as ten years, and the present perfect fits. Since would need a starting point.

The superlative of beautiful is most beautiful. Double superlatives are incorrect.

The participial phrase must modify the subject she. The other options create a dangling or disordered construction.

The present continuous passive is is being built, using the past participle.

The number of takes a singular verb, has. This contrasts with a number of.

Since is used with a point in time such as Monday, and the present perfect fits the continuing state.

The phrase as well as does not change the singular subject teacher, so was is correct.

In look forward to, the to is a preposition followed by the -ing form, hearing.

As the subject, the pronoun I is required, and convention places it after the other person.

An action completed before another past action takes the past perfect, had started.

After the preposition between, the objective pronoun me is required, not I.

No sooner is paired with than, and the auxiliary is inverted after it.

Seldom is already negative in sense, so adding not or never creates a double negative.

The idiom is afraid of something.

Parallel structure requires the same form for all items in the list, here the -ing form.

Parallel structure requires the same tense form for all verbs, here the simple past.

Each is singular and takes has. The noun after of must be plural, boys.

Between is used for two, so between the two children is correct. Among is used for more than two.

A period of time considered as a single unit takes a singular verb, is.

One agrees with a person. Agree to is used with a proposal or plan.

Apples are countable, so few is correct rather than little, and the verb is plural.

In the full comparison with a following verb, the subjective he is required. Than is correct.

Acting as a single unit, the collective noun jury takes has reached.

The correct construction is the reason is that. The reason is because is redundant.

When comparing two, the comparative with the is used, the more intelligent.

The present perfect continuous is has been living. The subject he takes has.

Patience is uncountable, so less is correct rather than fewer.

The idiom is good at a subject or skill.

The correct idiom is married to someone.

The correct option avoids piling up redundant phrases such as personally and myself.

In formal usage, the pronoun one is followed by one’s for consistency.

Senior is followed by to, not than.

After between, both pronouns take the objective case, him and her.

After hardly at the start, the auxiliary is inverted, and hardly is paired with when.

Revert already means to go back, so revert back is redundant.

Return already means to go back, so return back is redundant.

Not with anyone is correct. Not with no one is a double negative.

In a first conditional, the if-clause takes the present and the main clause takes will.

A general truth takes the simple present, and the unique sun takes the. Rises agrees with the singular subject.

The correct reflexive pronoun is himself. Hisself is non-standard.

Hardly is already negative, so pairing it with never or not creates a double negative.

At is used with clock times.

The adverb of frequency always is placed before the main verb.

Senior is followed by to, not than. The comparison uses to in formal usage.

Scissors is treated as plural and takes are.

Junior is followed by to, not than.

The past continuous was cooking sets the ongoing action interrupted by the past simple rang.

News is treated as singular despite ending in -s, so is is correct. The plural verbs are wrong.

University begins with a yoo sound, a consonant sound, so a is correct. An university is wrong.

With either-or, the verb agrees with the nearer subject, assistants, so are is correct.

The subject is one, which is singular, requiring is. The noun after of must be plural, friends.

Fewer is used with countable nouns such as cars. Less is used with uncountable nouns.

Deny is followed by the -ing form, stealing, not the infinitive.

The adverb of frequency usually is normally placed before the main verb.

Neither is singular and takes is. The noun after of must be plural, answers.

Prefer is followed by to when comparing two things. Prefers agrees with the singular subject.

Work is uncountable here, so much is correct rather than many, and it has no plural.

A number of takes a plural verb, were. The number of, by contrast, takes a singular verb.

Neither is singular and takes was.

Since is used with a starting point such as 2015, and the present perfect continuous fits.

Each is followed by a singular noun and a singular verb.

Each is singular and takes has. In formal usage the singular pronoun agrees with it.

The adverb beautifully modifies the verb sang. Sang is the correct past tense.

Water is uncountable, so little is correct rather than few, and the verb is singular.

After the preposition to, the objective pronouns her and me are required.

One is angry with a person in standard usage.

Superior is followed by to, not than, and is not compared with more.

After I wish, the subjunctive were is standard for an unreal present situation.

Faster is the comparative and is not preceded by more. Than is used in comparisons.

The adverb fluently modifies the verb speaks, which agrees with the singular subject.

Under alone correctly indicates position below. The other options add incorrect prepositions.

Advice is uncountable, so it takes no article and has no plural form.

Mathematics is singular although it ends in -s, so is is correct.

The idiom is interested in something.

Everybody is an indefinite pronoun taking a singular verb, is.

With neither-nor, the verb agrees with the nearer subject, friends, so were is correct.

The idiom is capable of doing something.

On is used with days of the week.

The subject he is singular, and as well as does not change it, so is is correct.

Be used to is followed by the -ing form, waking. It differs from used to plus base verb.

The idiom is fond of something.

Honest begins with a silent h, so the vowel sound requires an. The other options contain errors.

The construction too plus adjective plus to-infinitive is correct here.

Repeat already means to say again, so repeat again is redundant. The correct sentence avoids the repetition.

Across correctly indicates movement to the other side.

For indicates the intended recipient.

The real subject reasons is plural, so are is correct in the there-construction.

Twins are by definition two, but the correct option is the least redundant. The others add redundant words.

Treated as a single unit, the collective noun family takes is.

Among is used for more than two, so among the students is correct. Between is used for two.

The time marker an hour ago requires the simple past. The present perfect cannot take a specific past time.

As the object of meet, whom is the formally correct choice. The word order must be correct.

Arrive at is used with a specific point such as the airport.

The introductory phrase must modify the subject that follows, I. The other options misplace the modifier.

In formal usage, the relative pronoun who agrees with I, taking am.

In is used with years.

The adverb well follows the object in this construction.