If a bag is filled with books and pens,

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问题选择题

If a bag is filled with books and pens, it must belong to someone _________ works hard. [ ]

A. which

B. /

C. whom

D. who

答案

答案：D

选择题

No one expected house prices to fall，but ________ that’s exactly what happened.

A．moreover

B．thus

C．anyway

D．however

单项选择题

设随机变量X₁，…，X_n，…相互独立，记Y_n=X_2n-X_2n-1(n≥1)，概括大数定律，当n→∞时，

依概率收敛到零，只要X_n，n≥1满足

A．数学期望存在．
B．有相同的数学期望与方差．
C．服从同一离散型分布．
D．服从同一连续型分布．