"' is a set of drawing commands, in this case to move to the position 10, 50 and then draw the text in the double quotes."
'是一组绘图命令，在本例中是移动到位置10,50，然后绘制出双引号中的文本。
2
The single quotes are used because the double quotes are needed within the drawing command if more than one word is to be drawn, and you cannot have double quotes within double quotes.
使用单引号是因为如果需要绘制多个字，则绘图命令中需要使用双引号，而您不能在双引号中再用双引号。
3
This utility also lets you perform a simple drawing test and set the double-click speed and area.