(1)(某事持续的)一段时间(unbroken period of time during which sth lasts)[C]：a hot/cold～一段炎热/寒冷的日子;a long～of bad weather/health/sentry duty 长时间的坏天气/身体欠佳/站岗值勤;a short～in hospital 住院的短暂时日;stay at home for a～在家待了一段时间;〖同〗while，bit，break，interval，period;

(2)轮班(值)(turn at work or duty，etc)[N(at/on)]：a～at the plane's controls/at the wheel of the car/on the typewriter 轮流驾驶/开车/打字;take～s at carrying the baby 轮流抱那婴儿;do another～at the machine 在机器旁又轮了一次班