732、752交易金额限制为（）万元。
A.100
B.500
C.1000
D.1500
参考答案：C
下列关于直线电流周围磁场方向的示意图中，正确的是( )
Mr. Richard hasn’t got any time to play golf these days, because he is ______ in the research of bird language.
A．devoted
B．concentrated
C．buried
D．spared
