The role of two adults in everyday conversation consists of speaker and listener taking turns. One of the frequently -occurring phenomena in conversation is feedbacks. They are a hearer’s brief responses to the current speaker’s speech in a conversation. However, as one of the most common phenomena in conversations, feedbacks are usually not the focus of attention during conversations. They become noticeable only when they are either absent or too ubiquitous. Although some aspects of feedbacks have been examined by some studies, there has been no attempt to integrate the findings.This thesis studies feedbacks based on a 12-million-word subcorpus from the British National Corpus (BNC) of Spoken English. With the help of Sara (SGML Aware Retrieval Application), feedbacks are analyzed in terms of forms, positions, functions and sociolinguistic variation (power and context).From the study, we can see that feedbacks sometimes appear in the form of single word, but in most occasions, they appear in the form of more than one-word. If the feedbacks take the form of single-word, usually, they are fulfilling their transactional aims. They can perform the functions of contact, understanding, approval, appraisement/evaluation, acknowledgement, confirmation/ clarification and concession. While when they take the form of more than one word, they not only serve their transactional aims, but also serve their interaction aims. Feedbacks occur in two places based on the data from BNC. One is the non-natural pause of the speaker’s utterance (which we call overlap feedbacks);the other is the natural pause of the speaker’s utterance (which we call In-between feedbacks). When feedbacks occur in the non-natural pause of the speaker’s utterance, it means speakers have encountered some difficulties in their utterances. So listeners utter feedbacks not only to show they are listening, but also to encourage speakers to go on their utterance. When feedbacks occur in the natural pause, it just shows the listeners are listening. From the two socilolinguistic variations, power and context, we can draw the conclusion: the people with higher social status in a conversation usually utter more feedbacks than the people with lower social status. Especially, the former utters far more overlap feedbacks than the latter do. It is because when the inferior meet difficulties in a conversation, the superior’s feedbacks can be seen as encouragement, while the superior encounter difficulties, the inferior are not expected to utter too many feedbacks, otherwise, they will hurt the superior’s face. As for contexts, we get the conclusion that the more informal a context is, the more feedbacks are uttered. It is because in formal context, speakers usually know what they are going to say, and listeners are expected to focus their attention to their own ideas that is against the speakers’. So feedbacks are less used in formal occasions. While at informal situations, in order to understand correctly what speakers have said, the listener mustfeedback frequently, so the conversation can go smoothly.Feedbacks are very important to teachers and students in classrooms. So we also discussed the characteristics and benefits of feedbacks in classroom context.