A：大肠杆菌
B：酵母菌
C：噬菌体
D：肺炎球菌
“平民──将军──平民──总统──平民”这是一个人平凡而伟大的生涯故事。八年军旅，置生死于度外；八年总统，值国家最艰苦之时。他的名字已作为一个响亮的精神名词。那提议用他的名字为首都命名的人真是太智慧了。他是（ ）
— He's never advised to achieve a balance between his job and hobbies, ________? — _______. His parents and teachers often offer him advice.
— Talking loudly in a library is impolite.
— In fact, we should also ________ not to cough(咳嗽) or sneeze（打喷嚏）loudly in public.
⑴一份固体溶于水得无色透明溶液，加入足量BaCl2溶液，得沉淀6.63g，在沉淀中加入过量稀盐酸，仍有4.66g沉淀．
⑵另一份固体与过量NaOH固体混合后充分加热，产生使湿润的红色石蕊试纸变蓝色的气体0.672L（保准状况）．
下列说法正确的是（ ）
