你的意思是这样吗?这是一个jsfiddle
通过将父 ( .answerbox) 设置为position: relative,我可以将其设置.more为position:absolute并将其放置在该框中我喜欢的任何位置;在这种情况下,容器的右下角。
HTML
<div class="answerbox">
    <a href="#" class="more">Find out more</a>
</div>
CSS
.answerbox {
    height: 150px; /*Specify Height*/
    width:  150px; /*Specify Width*/
    border: 1px solid black; /*Add 1px solid border, use any color you want*/
    background-color: green; /*Add a background color to the box*/
    text-align:center; /*Align the text to the center*/
    position: relative;
}
.more {
    background: red;
    position: absolute;
    bottom: 0;
    right: 0;
    padding: 0 10px;
    height: 30px;
}
编辑 - 如果您想要按钮上的箭头图像
更新小提琴 
CSS
.more {
    background: url('http://dc390.4shared.com/img/AgV87Tvx/s7/arrow_small_right.png') no-repeat left center red;
    position: absolute;
    bottom: 0;
    right: 0;
    height: 30px;
    padding: 0 10px 0 20px; /* Extra padding left to make room for the button */
    line-height: 30px; /* Used to center the text vertically. Use the same value as the height.*/
}
编辑 - 让盒子随着内容而增长
更新小提琴 
CSS
.answerbox {
    width:  150px; /*Specify Width*/
    border: 1px solid black; /*Add 1px solid border, use any color you want*/
    background-color: green; /*Add a background color to the box*/
    text-align:center; /*Align the text to the center*/
    position: relative;
    padding: 10px 10px 40px;
}