按照保持时间的长短，记忆可分为（）
A.感觉记忆
B.机械记忆
C.短时记忆
D.长时记忆
E.识记
参考答案：A, C, D
China’s hurdler Liu Xiang was disqualified due to false start in the 60-metre event, _____ his rival Dayron Robles of Cuba an easy win of 7.66 seconds.
A．giving
B．given
C．to give
D．gave
我国电视标准规定场扫描的频率是（）
A.10Hz
B.20Hz
C.30Hz
D.40Hz
E.50Hz
