绝对压力
参考答案：
介质（液体、气体或蒸汽）所处空间的所有压力。绝对压力是相对零压力而言的压力。
18．On October 31st, known as Halloween, dozens of children ________ costumes knock at their neighbor’s doors and yell “Trick or Treat” when the door ________.
A．putting on; is open
B．dressed up in; opens
C．having on; is open
D．wearing on; open
假定窗体上有一个标签，名为Label1，为了使该标签透明并且没有边框，则正确的属性设置为( )。
A．Label1.BackStyle=0 Label1.BorderStvle=0
B．Label1.BackStyle=1 Label1.BorderStyle=1
C．Label1.BackStyle=True Label1.BorderStyle=True
D．Label1.BackStyle=False Label1.BorderStyle=False
