单采血浆就是把人体的血液经过离心机分离出血浆成分，把其余的成分还输到体内的一个过程。
参考答案：对
_______may be, one sometimes makes mistakes. [ ]
A. However a wise person
B. What a wise person
C. However wise a person
D. What wise a person
测定淬火钢的硬度，采用（）较适宜。
A.布氏硬度HBS
B.洛氏硬度HRC
C.维氏硬度
etimes makes mistakes. [ ]