牛黄的化学成分是:()
A.胆红素
B.胆汁酸
C.胆固醇
D.酸性肽
E.氨基酸
参考答案:A, B, C, D, E
A successful scientist needs _____ if he wants to make hypothesis (假设) of how processes work and how events take place.
A.permission
B.penetration
C.imagination
D.convention
来自同一界面的反射波,在相邻地震道上的激发、接收条件相近,地质情况相近,因此地震波的波形相似。