Interjections are words we use when we express our feelings strongly and which may be said to exist in language as conventional symbols of human emotions. In traditional grammars the interjection is regarded as a part of speech. But there is another view which regards the interjection as a sentence.
However a close investigation proves that interjection is a word with strong emotive meaning.
e. g. Oh, where are you going to, all you Big Steamers?
The interjection oh, by itself may express various feelings such as regret, despair, disappointment, sorrow, surprise and many others. Interjections can be divided into primary and derivative. Primary interjections are generally devoid of any logical meaning. Interjections such as: Heavens! Good gracious! God knows! Bless me! are exclamatory words generally used as interjections. It must be noted that some adjectives and adverbs can also take on the function of interjections - such as terrible! awfully! great! wonderful! splendid! These adjectives acquire strong emotional colouring and are equal in force to interjections.