某品种牛,无角基因P对有角基因p呈完全显性,现有一有角牛群,改造成无角牛群需通过()。
A.使用有角公牛
B.全使用无角公牛配种
C.使用有角母牛
D.淘汰有角公牛
参考答案:B
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Bs,取消其“可见”属性,运行时,在以下事件过程中,可以使快捷菜单响应鼠标右键的是( )
A.Private Sub Form_MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single) If Button=2 Then PopupMenu Bs,2End SubB.Private Sub Form_MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single) PopupMenu BsEnd SubC.Private Sub Form—MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single) PopupMenu Bs,0End SubD.Private Sub Form_MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single) If(Button=vbLeftButton)0r(Button=vbRightButton)Then PopupMenu BsEnd Sub
“八五”时期,我国制定了出口市场多元化战略。( )