必修一Welcome Unit一、重点词汇1. exchange [ɪksˈtʃeɪnʤ] n. 交换; 交流 vt. 交换; 交流;交易; 兑换2. lecture [ˈlektʃə] n. 讲座;讲课;教训 vi. (开)讲座;讲课 vt.训斥3.
答案:The instant the manned spaceship landed safely after flying in space for a week， the quiet launch centre exploded with joyful cheers.
