图中()具有水层的电性特征。
A.1号层
B.2号层
C.3号层
D.4号层
参考答案:D
十进制数215用二进制数表示是
A.1100001
B.11011101
C.0011001
D.11010111
Questions 11~14
A. He is a company manager. B. He is a repairman. C. He is a taxi driver.D. He is a dentist.