当你的电脑无法获得正确的金额时,你知道这是一个错误！
我没有丝毫想到为什么会这样：
_root.attachMovie("clippy","aClip",_root.getNextHighestDepth());
trace("alpha 1 = "+aClip._alpha);
aClip._alpha = 0;
trace("alpha 2 = "+aClip._alpha);
aClip._alpha += 20;
trace("alpha 3 = "+aClip._alpha);
aClip._alpha = 20;
trace("alpha 4 = "+aClip._alpha);
输出是：
alpha 1 = 100 alpha 2 = 0 alpha 3 = 19.921875 alpha 4 = 19.921875
19.921875应该是20！
