private sub command_click() for i=1 to4 x=3 for j=1to3 for k=1 to 2 x=x+3 next k next j next i 输出输出str（x）

private sub command_click() for i=1 to4 x=3 for j=1to3 for k=1 to 2 x=x+3 next k next j next i 输出输出str（x）
private sub command_click() for i=1 to4 x=3 for j=1to3 for k=1 to 2 x=x+3 next k next j next i 输出
输出str（x）

private sub command_click() for i=1 to4 x=3 for j=1to3 for k=1 to 2 x=x+3 next k next j next i 输出输出str（x）
最外层循环每次初始化x=3,那么最外层就不用考虑了,只考虑x=3
两层内循环总循环次数为2*3=6,每次累加3,6次累加了18,再加上前面3,就是21