A.左上角为原点，x轴正方向为水平向右，y轴正方向为竖直朝上
B.中间为原点，x轴正方向为水平向右，y轴正方向为竖直朝上
C.左下角为原点，x轴正方向为水平向右，y轴正方向为竖直朝下
D.左上角为原点，x轴正方向为水平向右，y轴正方向为竖直向下

A.WM_TIME
B.WM_TIMER
C.WM_ON_TIME
D.WM_COMMAND

A.MFC
B.MSDN
C.API
D.SDK

A.WM_KEYDOWN
B.WM_LBUTTONDOWN
C.WM_LEFT
D.WM_RBUTTONDOWN

A.VK_A
B.WM_KEYDOWN
C.A
D.DIK_A

A.VK_UP
B.WM_KEYDOWN
C.WM_KEYUP
D.VK_DOWN

A.VK_UP
B.WM_KEYDOWN
C.WM_KEYUP

A.WM_PAINT
B.WM_COMMAND
C.WM_CREATE
D.WM_CLOSE

A.Visible
B.Grayed
C.Enable
D.Separator

A.HWND
B.HDC
C.HINSTANCE
D.HFONT

A.g_hWnd
B.m_hWnd
C.g_pWnd
D.m_pWnd