蛋白质所形成的胶体颗粒,在下列哪种条件下不稳定()
A.溶液pH小于pI
B.溶液pH大于pI
C.溶液pH等于pI
D.溶液pH等于7.4
E.在水溶液中
参考答案:C
Make a tentative guess _____ Peking Man _____ have done and used thousands of years ago. [ ]
A. that; may
B. that; must
C. what; may
D. what; should
随机误差等于误差减去系统误差。