【单选题】关于胰腺头部周围血管的解剖,正确的是
C.
胰头上方为肠系膜上动脉及肝动脉,后方为下腔静脉
D.
胰头上方为肠系膜上静脉及肝动脉,后方为下腔静脉
【多选题】两列波发生了干涉现象,得到了干涉图样,则( )
B.
振动加强的质点的位移,有时会小于振动减弱的质点的位移
【判断题】Edward was known as the "Confessor" because of his reputation for saintliness and he established the Westminster Abbey.
【多选题】两列波发生了干涉现象,得到了干涉图样。则
A.
振动加强的质点,始终处于最大位移处;振动减弱的质点,始终处于最小位移处。
C.
两列波的振动方向一定平行,振动相位差一定为定值