Some important tips

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Rule : –
In a “not only … but also .. “sentence, the verb should agree with the noun or pronoun mentioned second, that is, the one after but also because this is the part being emphasised.

Incorrect: Not only the students but also the teacher were responsible for what happened in the class.(Incorrect)
Not only the students but also the teacher was responsible for what happened in the class. (Correct)
Rule: –
Scarcely should be followed by when, not by than.
Scarcely had he arrived than he had to leave again. (Incorrect)
Scarcely had he arrived when he had to leave again.(Correct)
Rule :
Correlative conjunctions should be followed by the same part of speech.
He neither agreed to my proposal nor to his.(Incorrect)
Correct: He agreed neither to my proposal nor to his. (Correct)
Rule :
‘Lest’ must be followed by ‘should’ or by nothing at all and ‘Such’ must be followed by
‘as’.
Work hard lest you will fail. (Incorrect)
Work hard lest you should fail. (Correct)
Work hard lest you fail. (Correct)
He is such a writer that everybody should read his books. (Incorrect)
He is such a writer as everybody should read his books. (Correct)
Rule :
Though’ is followed by ‘yet’ and not by ‘but’.
Though he is poor but he is honest. (Incorrect)
Though he is poor, yet he is honest. (Correct)
Rule :
When comparison is made by means of a comparative, the thing compared should be
excluded from the class of things with which it is compared by using ‘other’ or some such word.And In Superlative Degree the thing com-pared should include the class of things with which it is compared.

In Comparative Degree Matter
He is cleverer than any boy in the class. (Incorrect)
He is cleverer than any other boy in the class.(Correct)
In Superlative Degree Matter
He is the strongest of all other men. (Incorrect)
He is the strongest of all men. (Correct)
Note :- Double comparatives and superlatives should not be used.
Example :- He is the most cleverest boy in the class. (Incorrect)
He is more wiser than his brother . (Correct)