Page through a long file super rapidly (holding your thumb on the Page Down button, notice the pattern of blurry text on the screen, and look for strange variations in that pattern.

• 极快地去游览一个长文件（用手指一直按着下翻页键），注意屏幕上出现地虚文本的样子，同时注意寻找样子有没有奇怪的变化。