sù / dù / hé / shí / jiān / wǎng / wǎng / chéng / fǎn / bǐ / sù / dù / yuè / kuài / shí / jiān / yuè / duǎn速度和时间往往成反比,速度越快时间越短。Speed and time are often inversely proportional; the faster the speed, the shorter the time.