What _____ reading aloud to practice pronunciation?[ ]
A. of
B. about
C. around
答案:B
抗体与抗原结合的部位是()
A.重链的C区
B.Fc片段
C.轻链的Ⅴ区
D.重链的Ⅴ区
E.重链和轻链的Ⅴ区
下列不属于半导体材料的是( )
A.硅
B.锗
C.砷化镓
D.铜