东汉时期发明的、为了节约人力、提高冶炼质量,在冶净铁方面的重大发明是[ ]
A.水排
B.提花机
C.印刷术
D.翻车
答案:A
混凝土立方体抗压强度应达到( )的保证率。
A.90%
B.95%
C.98%
D.100%
设已经在菜单编辑器中设计了窗体的快捷菜单,其顶级菜单为Bt,取消其“可见”属性,运行时,在以下事件过程中,可以使快捷菜单相应鼠标右键菜单的是
A.Private Sub Form_MouseDown(Button As Integer, Shift As Integer,_ X As Single, Y As Singl If Button=2 Then PopupMenu Bt, 2 End Sub
B.Private Sub Form_MouseDown(Button As Integer, Shift As Integer, _ X As Single, Y As Singl PopupMenu Bt End Suh
C.Private Sub Form MouseDown(Button As Integer, Shift As Integer, _ X As Single, Y As Singl PopupMenu Bt,0 End Sub
D.Private Sub Form_MouseDown(Button As Integer, Shift As Integer, _ X As Single, Y As Singl If (Button=vbLeftButto Or ( Button=vbRightButto Then PopupMenu Bt End Sub