原文地址：

简化版地址：

感想：笨蛋，想不出自己的东西。。。

HTML代码：

            
                        
        
            
         
Who Am I
            
         
                Who gives you milk?                cow            
            
         
                Who likes to eat flies？                frog            
            
         
                Who have large claws?                crab            
        
        
    

CSS代码：

html, body {
          margin: 0;    padding: 0;    height: 100%;    display: flex;    justify-content: center;    align-items: center;    background-color: green;    color: gold;    text-align: center;}p {
          width: 400px;    height: 2.5em;    font-size: 24px;    border: 2px solid gold;    line-height: 2.5em;    border-radius: 10px;    font-family: sans-serif;    letter-spacing: 2px;    word-spacing: 2px;    box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.2);    position: relative;    /* 溢出隐藏 */    overflow: hidden;}p span {    /* 绝对定位,使两个span重合 */     position: absolute;    /* 占父元素全部 */    width: 100%;    top: 0;    left: 0;    /* 使之有动画效果 */    transition: 0.5s ease-out;}p .question,p:hover .answer {
          left: 0;}p:hover .question {
          left: 100%;}p .answer {
          color: whitesmoke;    font-size: 1.1em;    text-transform: uppercase;    background: rgba(0, 0, 0, 0.1);    left: -100%;}