【多选题】关于诊断性能指标特点( ) A、 灵敏度 B、 特异性 C、 诊断性能 D、 预测值 E、 似然比
【单选题】Which of the following is generally not included in a research proposal?
【简答题】交流毫伏表是否可以用来测量直流电压的大小?为什么?
【判断题】Generally, espresso is the thickest.
【简答题】Generally speaking, ____________ (being on time) is a must for employees.
【简答题】It is generally said that the British are better at the last.
【简答题】Translation: 2. It is generally said that the British are better at the last.
【简答题】实验室制备苯乙酮的化学方程式为: 制备过程中还有CH 3 COOH+AlCl 3 ―→CH 3 COOAlCl 2 +HCl↑等副反应。 主要实验装置和步骤如下: (Ⅰ)合成:在三颈瓶中加入20g无水三氯化铝和30mL 无水苯。为避免反应液升温过快,边搅拌边慢慢滴加6mL 乙酸酐和10mL无水苯的混合液,控制滴加速率,使反应液 缓缓回流。滴加完毕后加热回流1小时。 (Ⅱ)分离与提纯:①边搅拌边慢慢...