在电脑的存储设备中,数据存取速度从快到慢的顺序是()。
A.软盘、硬盘、光盘、内存
B.内存、硬盘、光盘、软盘
C.软盘、硬盘、内存、光盘
D.光盘、软盘、内存、硬盘
参考答案:B
In my opinion, all Mr. Li ______ good to his students in his class at present. He is very strict with them in
their studies.[ ]
A. does does does
B. does do did
C. does does do
D. did do does
用两步滴定法滴定阿司匹林片的含量,是因为()
A.方法简单,结果准确
B.片剂中有淀粉影响测定
C.阿司匹林片易水解
D.片剂都用两步滴定法
E.有酸性稳定剂和酸性水解产物影响