据对大量化石的研究分析，人类最可能最早出现在 [ ]
A．非洲
B．亚洲
C．欧洲
D．美洲
A
I don't think he could have done such a stupid thing last night, ______? [ ]
A. do I
B. could I
C. did he
D. has he
祸不单行可以用来形容( )。
A．单一性压力
B．同时性叠加压力
C．继时性叠加压力
D．破坏性压力
