施用钾肥能增强农作物的抗倒伏能力.下列物质可用作钾肥的是
A:NH4HCO3
B:K2CO3
C:CO(NH 2 )2
D:Ca(H2PO4 )2
若2弧度的圆心角所对的弧长为4cm,则这个圆心角所夹的扇形的面积是( )
Dim n As Integer, s As Integer, i As Integer
n=Val(Text1.Text)
s=0
For i=1 To n Step 2
s=s+i
Next i
Text2.Text=Str(s)
图1
i=1
Do While i<=n
i=i+2
Loop
图2
当n的值为10时,关于该两段程序,下列说法不正确的是( )
The wind moved _______ and blew the kite away.