单选题 The human ear contains the organ for hearing and the organ for balance. Both organs involve fluid-filled channels containing hair cells that produce electrochemical impulses when the hairs are stimulated by moving fluid. The ear can be divided into three regions: outer, middle, and inner. The outer ear collects sound waves and directs them to the eardrum separating the outer ear from the middle ear. The middle ear conducts sound vibrations through three small bones to the inner ear. The inner ear is a network of channels containing fluid that moves in response to sound or movement. To perform the function of hearing, the ear converts the energy of pressure waves moving through the air into nerve impulses that the brain perceives as sound. Vibrating objects, such as the vocal cords of a speaking person, create waves in the surrounding air. These waves cause the eardrum to vibrate with the same frequency. The three bones of the middle ear amplify and transmit the vibrations to the oval window, a membrane on the surface of the cochlea, the organ of hearing. Vibrations of the oval window produce pressure waves in the fluid inside the cochlea. Hair cells in the cochlea convert the energy of the vibrating fluid into impulses that travel along the auditory nerve to the brain. The organ for balance is also located in the inner ear. Sensations related to body position are generated much like sensations of sound. Hair cells in the inner ear respond to changes in head position with respect to gravity and movement. Gravity is always pulling down on the hairs, sending a constant series of impulses to the brain. When the position of the head changes — as when the head bends forward — the force on the hair cells changes its output of nerve impulses. The brain then interprets these changes to determine the head's new position.

单选题 What can be inferred about the organs for hearing and balance?

单选题 Hearing involves all of the following EXCEPT______.

【正确答案】 A

【答案解析】解析：A选项不是hearing的内容而是speaking的组成部分，而其余三项都与hearing有关。“fluid—filled channels containing hair cells that produce electrochemicalimpulses when the hairs are stimulated…“对应B选项： “…bones of the middle earamplify and transmit the vibrations…”对应C选项： “…the ear conveys the energy ofpressure waves moving through the air into nerve impulse”对应D选项。

单选题 It can be inferred from paragraphs 2 and 3 that the cochlea is a part of______.

【正确答案】 D

【答案解析】解析：第二段最后一句“The inner ear is a network of channels containing fluid…”，第三段中“…the cochlea，the organ of hearing”和“…the fluid inside the cochlea．Haircells in the cochlea convert the energy of the vibrating fluid…”可得知，内耳是包含液体的渠道网络，而该液体位于耳蜗中，因此，耳蜗是内耳的一部分。故答案为D。

单选题 What can be inferred from paragraph 4 about gravity?

单选题 What does "membrane" most probably mean?

【正确答案】 C

【答案解析】解析：词汇题。member为混淆词，与membrane形似。定位到第三段“…amplifyand transmit the vibrations to the oval window，a membrane on the surface of the cochlea，the organ of hearing”可知，membrane为耳蜗表层的一种东西，并且能放大并传播震动。根据上下文，只有“薄膜”的含义最能体现这种功能。故本题答案为C。