填空题 Yesterday my doctor gave me some tablets. There were five in the box. He told me to take one every half hour. How long did they last?
【正确答案】
【答案解析】2 hours[解析] 医生给了我一盒药，一盒里面共装5粒，每半小时服1粒，如果连续服用，共能服用2个小时。选项C正确。