信用货币具有的特征是（）。
A、是价值符号
B、是负债货币
C、可以任意发行
D、国家强制性
参考答案：A, B, D
American students take part in a wide variety of after-school activities _______ they develop their social skills.
A．where
B．which
C．that
D．what
斜面花坛
