The school checks the air（空气）/eə/ report（报告）/rɪˈpɔːt/ every morning. On Wednesday（星期三）/ˈwenzdeɪ/, the report showed a very（很；非常）/ˈveri/ unhealthy（不健康的）/ʌnˈhelθi/ level（等级；水平）/ˈlevl/, and the sky（天空）/skaɪ/ above（在……上方）/əˈbʌv/ the sports（体育运动）/spɔːts/ field（场地；运动场）/fiːld/ looked grey（灰色的）/ɡreɪ/. The physical（身体的；体育的）/ˈfɪzɪkl/ education（教育）/ˌedʒuˈkeɪʃn/ class was going to practise（练习）/ˈpræktɪs/ running（跑步）/ˈrʌnɪŋ/ outside（在户外）/ˌaʊtˈsaɪd/, but Ms Gao changed the plan before students left the classroom.

“Outdoor（户外的）/ˈaʊtdɔː/ practice will be moved indoors（在室内）/ˌɪnˈdɔːz/ today. High pollution（污染）/pəˈluːʃn/ can make（使得）/meɪk/ it harder to breathe（呼吸）/briːð/ during strong（强烈的；剧烈的）/strɒŋ/ exercise（运动；锻炼）/ˈeksəsaɪz/. We will do exercise（锻炼）/duː ˈeksəsaɪz/ in the gym（体育馆）/dʒɪm/ because of（因为）/bɪˈkɒz əv/ the air report. This will protect you from（保护……免受……）/prəˈtekt juː frɒm/ the dirty（污浊的；脏的）/ˈdɜːti/ air while keeping（使保持）/kept/ everyone（每个人）/ˈevriwʌn/ active（活跃的；活动着的）/ˈæktɪv/.”

Some（一些）/sʌm/ students thought an indoor（室内的）/ˈɪndɔː/ lesson would（会；将会）/wʊd/ be boring（无聊的）/ˈbɔːrɪŋ/. Ms Gao divided（分成）/dɪˈvaɪdɪd/ the gym into（进入；分成）/ˈɪntuː/ four activity（活动）/ækˈtɪvəti/ areas（区域）/ˈeəriəz/. One area had a slow warm-up（热身）/ˈwɔːm ʌp/, one had easy（简单的）/ˈiːzi/ ball（球）/bɔːl/ games（游戏；比赛）/ɡeɪmz/, one had balance（平衡）/ˈbæləns/ practice, and one had a short walking（步行的）/ˈwɔːkɪŋ/ course（路线；课程）/kɔːs/. Each group（小组）/ɡruːp/ spent（花费（时间））/spent/ six minutes（分钟）/ˈmɪnɪts/ in an area and then changed places（位置；区域）/ˈpleɪsɪz/. The indoor plan kept the students active without making them breathe too（太；过于）/tuː/ hard（用力地；困难的）/hɑːd/.

Ms Gao also（也；还）/ˈɔːlsəʊ/ told（告诉）/təʊld/ everyone to watch how they felt（感觉）/felt/. “If you cough（咳嗽）/kɒf/ or feel pain（疼痛）/peɪn/ in your chest（胸部）/tʃest/, stop and take a break（休息一下）/teɪk ə breɪk/.” No（没有人；不）/nəʊ/ one tried to win（赢得）/wɪn/ a race（比赛）/reɪs/ or hide（隐藏；隐瞒）/haɪd/ a problem. As a result（因此）/æz ə rɪˈzʌlt/, the class finished all（全部）/ɔːl/ four activities safely（安全地）/ˈseɪfli/. They drank（喝）/dræŋk/ water and stayed away from（远离）/steɪd əˈweɪ frɒm/ the smoky（有烟尘的）/ˈsməʊki/ field for the rest of the morning.

Before lunch, Ms Gao checked the report again（再次）/əˈɡen/. The level was still unhealthy, so the field remained（保持）/rɪˈmeɪnd/ empty（空的）/ˈempti/. The students had exercised for thirty minutes indoors and learned（懂得；学会）/lɜːnd/ that changing a plan can help them keep healthy（保持健康）/kiːp ˈhelθi/.