肝素抗凝的主要机制是

A．抑制凝血酶原被激活

B．增强抗凝血酶Ⅲ与凝血酶的亲和力

C．去除Ca²⁺

D．抑制因子X激活

E．促血小板提供磷脂表面

下列事件过程的功能是：建立一个名为Datal的随机文件，存放角度值及这些角度的正弦函数值和余弦函数值，角度为1，2，3，…，90。请选择正确的程序段是( )，将程序补充完整。
Private Type Ang
K As Integer
Sinx As Single
Cosx As Single
End Type
Dim Ksc As Ang
Private Sub Form_Click()
Dim Y As Single
Dim i As Integer
Dim Ksc As Ang
Open ______
Y=3.14159/180
For i=1 To 90
Ksc.K=i
Ksc.Sinx=Sin(i*Y)
Ksc.Cosx=Cos(i*Y)
Next i
Close #2
End Sub

A．"..\Datal.txt"For Random As #1 Len=10 Put #1，i，Ksc

B．"..\Datal.txt"For Random As #1 Len=10 Put #1，Y，Ksc

C．"..\Datal.txt"For Random As #1 Put #1，i，Ksc

D．"..\Datal.txt"For Random As #1 Put #1，Y，Ksc