脑结构成像的技术有（）
A.CT
B.MRI
C.PET
D.fMRI
E.B超
参考答案：A, B
截至2006年底，中国企业发行存托凭证的家数达到73家，发行存托凭证69种。 ( )
—How about your journey to Mount Emei?
—Everything was wonderful except that our car ________ twice on the way.[ ]
A. slowed down
B. broke down
C. got down
D. put down
