经典的分子遗传学中心法则是()
A.A
B.B
C.C
D.D
E.E
参考答案:C
120. --- ________ are your business hours?
--- From 9:00 a.m. to 5:00 p.m.
A.What
B.How
C.Which
D.Where
设A=αβT+βαT,其中α,β是相互正交的三维单位列向量. (Ⅰ)求|A|. (Ⅱ)验证α+β,α-β是A的特征向量. (Ⅲ)证A~Λ,并求Λ.