标准V形块两斜面的夹角有哪几种()。
A.30
B.45
C.60
D.90
E.120
参考答案:C, D, E
The Acropolis ________ in the 5th century B. C. at a high altitude above the city in honour of
Athena, the goddess of Athens.[ ]
A. constructed
B. was constructed
C. has been constructed
D. is being constructed
MRI对比增强常用的对比剂是()
A.泛影葡胺
B.GD-DTPA
C.优维显
D.欧乃派可
E.伊索显