The doctor must be 24 hours a day, 7 days a week in the boarding school. A. on callB. by

发布时间：2020-08-17 06:50:18

The doctor must be      24 hours a day, 7 days a week in the boarding school.
A. on call
B. by hand
C. in sight
D. on spot

网友回答

(答案→)A. on call
B. by hand
C. in sight
D. on spot
解析：考查介词短语：A. on call随叫随到，待命，B. by hand在手边，C. in sight在视野以内，D. on spot在出事地点，句意：在寄宿学校，这个医生必须一星期7天一天24小时待命。选A。
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