亚马逊书店成功的原因之一在于它重视了个性化的客户服务。
参考答案：对
—How is Dennis getting along with his work?
—Well, he could always _____ a new idea for increasing sales.
A．call up
B．bring about
C．lead to
D．come up with
A．变压器输出端所接电压表的示数为20V
B．变压器的输出功率为200W
C．变压器输出端的交流电的频率为50Hz
D．穿过变压器铁芯的磁通量变化率的最大值为20/n2Wb/s
V
/n2Wb/s