RS—232C逻辑“0”的电平为( )。
A．大于+3V
B．小于-3V
C．大于+15V
D．小于-15V
参考答案：A
以下哪种药物较易引起白细胞减少（）
A.氯丙嗪
B.氯氮平
C.奋乃静
D.氟哌啶醇
E.三氟拉嗪
Great importance has been ________ education since 1985, when the first educational reform began. [ ]
A. attached to
B. devoted to
C. linked to
D. used to
