Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 5 to 8

Face-to-face conversation is a two-way process: you speak to me, I reply to you and so on. Two-way (5)_____depends on having a coding system that is understood by both sender and receiver, and an agreed convention about signaling the beginning and end of the (6)_____. In speech, the coding system is the language like English or Spanish; the convention that one person speaks at a time may seem too obvious to mention. In fact, the (7)_____that people use in conversations and meetings are often non- verbal. For example, lowering the pitch of voice may mean the end of a sentence; a sharp intake of breath may signal the desire to interrupt, catching the chairman’s eye may indicate the desire to speak in a formal setting like a debate, a clenched fist may indicate anger. When these (8)_____signals are not possible, more formal signals may be needed.