[单项选择]Children are becoming more inactive in study because ________. A. they watch TV too much B. they have done too much homework C. they have to fulfill too many duties D. teachers are too strict with them
参考答案:A 答案解析:题目中的inactive可以在原文第三段中找到对应的词passive,passivity,Television contributes to children's passivity所表示的意思正好与
第17题: [单项选择]延长局部麻醉药作用时间的常用办法是() A. 加入少量肾上腺素 B. 注射麻黄碱 C. 增加局部麻醉药浓度 D. 增加局部麻醉药溶液的用量 E. 调节药物溶液pH 参考答案:A 答案解析:肾上腺素可收缩用药部位的血管,减慢药物吸收速度,既能延长局部麻醉药的作用时间,又可减少吸收中毒的机会。