Vocabulary vacuum /'vækj ʊə m/ n. 真空 durable /'d ʊ r ə bl/ adj.耐用的 insulation /, ɪ ns ə 'le ʃə n/ n. 隔热,绝缘 inflatable / ɪ n'flet ə bl/ adj.需要充气的 sac /sæk/ n. 囊,液囊,气囊 1. Listen to the recording and answer the following questions. 1) What is the speaker’s purpose? 2) What would cause an unprotected human body to explode in outer space? 3 ) What is the function of the torso? 4) What is the function of “bladder” of oxygen?