A．He has never seen a fossil that old.B．It could be many millions of years old.C．It is
A. He has never seen a fossil that old.
B. It could be many millions of years old.
C. It is probably a recent specimen.
D. He will ask tile lab how ()Id it is.
【B4】
A. used
B. mentioned
C. signed
D. received
A．knockedB．forcedC．pushedD．tried
A. knocked
B. forced
C. pushed
D. tried
_____首先提出了循环行为论。
A. 伯法
B. 梅奥
C. 亨利.明茨伯格
D. 玛丽.福莱特
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