设A为三阶方阵，且∣A∣=2，则∣-2A∣=（）.
A. -16
B. -4
C. 4
D. 16
根据1996年11月国家经贸委颁发的《机电设备招投标管理办法》规定，以下说法不正确的是( )。
A. 合同签订时，招标文件不作为经济合同的组成部分
B. 投标单位中标后拒签合同，应赔偿不超过中标金额的2%
C. 合同签订时投标文件作为经济合同的组成部分
D. 中标通知发出后，设备需方拒签合同，赔偿金额为中标金额的2%
From the passage we know that the nerve impulses in human beings ______.
A. are lack of differentiation in quality
B. are similar in size, number, and arrangements
C. reveal qualitative diversity
D. spasmodically pass through the nervous system
From paragraph 1 we can learn that by 1950, ______.
A. scientists have reached a consensus on the relationship between brain processes and mental experience
B. variations in nerve cells are proved to be significantly correlated with mental experience
C. attempts to correlate mental experience with brain processes have been viewed with pessimism
D. scientists are indifferent to the manifold dimensions of mental experience
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