真空泵是化工操作中使系统获得低于大气压力的一种机械。
参考答案：对
Sedative-hypnotic drugs are used to treat which of the following problems
A．Hallucinations and delusions.
B．Anxiety and insomnia.
C．Obsessive-compulsive disorder (OCD).
D．Attention deficit hyperactivity disorder (ADHD).
区域部门化
