如图所示，胎心听诊最清楚的部位是____。
参考答案：E
To learn English well,we should find opportunities to hear English _______as much as
we can. [ ]
A. speak
B. speaking
C. spoken
D. to speak
A．，正电荷
B．，正电荷
C．，负电荷
D．，负电荷
，正电荷
，正电荷
，负电荷
，负电荷