说明：  在VB中绘制实时曲线是比较难的，一般要应用第三方控件或是Windows API函数来完成，但是如果你对实时曲线的要求不是很高，只要能表示出当前的一般情况的话，我们可以直接应用VB提供给我们的空间来完成。
(Curve in VB is more difficult to draw real-time, usually to apply third-party controls or the Windows API function to complete, but if you are the requirements for real-time curve is not very high, can be expressed as long as the current general situation, we can VB application to provide us the space to complete.)