Question

What are you laughing_ _ _ _ _ _?
A. Of
B. In
C. With
D. For

Answer 1

Hint: First we must know the meanings of all the options and choose the option which will be grammatically correct. Also, we must see that the selected option will make the sentence meaningful.

Complete answer: This sentence requires a particular Preposition from given options to be completed. Let’s know what prepositions are: In, at, on, for, to, inside, outside are some of the examples of Preposition which connect the people, time, object, and location of a sentence.
Let’s examine and analyze the given options first.

Of: the Preposition Of shows the relation or belonging with the subject. For example; “He is the brother of my friend”.But the given sentence is asking the purpose of the action. So it’s an inappropriate option.

In: this Preposition shows the Location of the subject. For example; “She is in her room”. But the given sentence is asking the purpose of the action. So it’s an inappropriate option.

With: this shows that the subject is accompanying someone. For example; “She was studying with her sister”. But the given sentence is looking for the purpose of action. So it’s an inappropriate option.

For: option (D) is an absolutely correct option for showing the purpose of the action.
So the correct sentence is “What are you laughing for?”.

Note:
To understand such questions the study of ‘Preposition’ is required so that we can write correct sentences. There are about 150 prepositions in English. Yet this is a very small number when you think of the thousands of other words (nouns, verbs, etc). Prepositions are important words.