Prepositions “at”, “on” and “in” The prepositions “at”, “on” and “in” are function words which do not have clear lexical meanings and obvious concepts associated with them. However, these prepositions are important because they specify grammar relations by connecting the content words such as nouns, verbs, adjectives and adverbs to a larger grammatical context. For instance, polar bears hibernate in the winter. This sentence shows that polar bears hibernate during or throughout the winter by just using the preposition “in” before “the winter”. The meaning of the sentence changes if we replace “in” with “at” or “on” in the above sentence. In terms of morphology, “at”, “on” and “in” are all morphemes of a single syllable. Morpheme is an arbitrary union of a sound and a meaning (or grammatical function) that cannot be further analyzed. Even though the structure of these morphemes are simple as they are all made up of two alphabets and one syllable, but their functions are not limited. They can be used in other contexts apart from the context related to time. “At” is used as a preposition to show a point in certain space. For example, he was standing at the door. The usage of “at” point out specifically that he was standing right at the door. It is used to show an intended aim or object towards which a thing or action is directed. For example, he shot at the bird, but missed it. It can be used to show the cause of an action or feeling as in this sentence “I was surprised at his behaviour.” “In” can be placed in other classes of word such as adverbs and adjectives other than prepositions. As an adverb, it means to be present especially at home or under the roof of a building. For instance, I’m afraid Mr. Jones is out, but he’ll be in again soon. It has the meaning of fashionable when it is used as an adjective as shown in this sentence “That new restaurant is the in place to go now.” It can also act as a bound morpheme such as a prefix in these adjectives “insensitive” and “inattention”. However, based on morphology, two different morphemes of different meaning may be pronounced identically. Therefore, we can make a conclusion that the morpheme “in” alone which used as a preposition, adverb or adjective is totally different from the “in-” which used as a prefix or suffix. “On” is quite similar to “in” in the sense that it can also be used as an adverb or adjective besides than preposition. This usage of “on” can be shown in this sentence “ We worked on all night.” where “on” means continuously and non-stopping. It acts as a bound morpheme as in “on-air” and “oncoming” which are adjectives. In conclusion, there is a reason behind the frequent usage of these three words “at”, “in” and “on” in our daily conversation. It is because they are multifunctional and they can be placed in different classes of word which allows us to use them in different contexts although they are well known as prepositions and the usage of them as prepositions alone seems to be confusing and challenging enough for English learners.