框构涵沉降缝不应设在（）下方，可设在两线中间。
参考答案：轨道
Langlang plays the piano very well. He is one of pianists in China.
A．famous
B．more famous
C．most famous
D．the most famous
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