GPS,即全球定位系统,它是利用分布在约2万公里高空的多颗卫星对地面目标的状况进行精确测定以进行定位、导航的系统。
参考答案:对
设在工程中定义了如下类型: Type stutype ino As Integer strname As String*20 strsex As String* 1 smark As Single End Type在窗体上正确使用这个类型的是下列哪个操作( )。
A.Sub Commandl_Click0 Dim student As Stutype With student .ino = 12 . strname = smith .strsex = .smark = 89 End With End Sub
B.Sub Commandl_Click0 Dim student As Stutype With student .ino = 12 .strname = "smith" .strscx = "男" .smark = 89 End With End Sub
C.Sub Commandl_Click0 Dim student As Stutype With Stutype ino = 12 .strname = "smith" .strsex = "男" .smark = 89 End With End Sub
D.Sub Command1 _Click() Dim student As Stutype With student .ino = 12 .strname = "smith" .strsex = "男" .smark = 89 End student End Sub
水冷却后,除了会凝固成冰晶体外,还会形成玻璃态。它是由液态水急速冷却到-108℃时形成的,玻璃态的水与普通液态水的密度相同。下列说法正确的是[ ]
A.水由液态变为玻璃态,体积减小
B.水由液态变为玻璃态,体积膨胀
C.水由液态变为玻璃态是物理变化
D.水由液态变为玻璃态是化学变化