Fill in the blank using a suitable option.
Work hard, lest you ____ fail.
a) may
b) can
c) should
d) would

Hint: The underlined word, ‘very’ is used to elaborate the speed of the person who is running.

Complete step by step solution:
In the given question we have to figure out the part of speech of the underlined word in the given sentence.
In the sentence, the word ‘very’ emphasizes on the speed of the running. It is used to denote the degree of the speed. Such words are called adverbs. Adverbs of degree are used to express the intensity of an action. Hence, the correct answer is option ‘A’, ‘adverb’.
Let us see why the other options are incorrect.
Option ‘B’, adjective is incorrect as the word ‘very’ is not describing a noun, as adjectives do.
Option ‘C’, verb is incorrect as ‘very’ is not an action.
Option ‘D’, noun is incorrect as ‘very’ does not refer to a person, place, animal or object. It is a word used to express the degree of an action.

Note: To answer questions such as this, it is necessary to have a basic but clear idea about the meanings and usages of adverbs, adjectives, verbs and nouns. If this is well understood, it would be very easy to solve questions that fall into this category.