差速离心法的优点有（）。
A.样品处理量大
B.分离时间短
C.重复性高
D.操作复杂
E.离心分辨率较差
参考答案：A, B, C
The speaker walked out of the hall, __ happily with the teacher, and ___ by a group of students.
A．talking, followed
B．to talk, followed
C．talking, to be followed
D．to be talking, to followed
压力的英制单位是（）。
A、1kgf／cm2
B、psi
C、Pa
D、MPa
E、kPa
