构成有效市场的必要条件除了人口之外，还需要()。
A.法制
B.购买力
C.技术
D.文化环境
参考答案：B
对客户解除挂失有什么要求？
Although he has become wealthy, Mr. Wood remains he used to be, modest and friendly.
A．which
B．where
C．what
D．that
