"float: left;" div 不换行显示

<div id='p'>
    <div id='c1'>
    </div>
    <div id='c2'>
    </div>
    <div id='c3'>
            <span id='s1'>
            </span>
            <span id='s2'>
            </span>
            <span id='s3'>
            I want to display myself in the same line with element #c1, #c2, #c3!
            </span>
    </div>
</div>

#p {
  height: 30px;
  width: 400px;
  background-color: yellow;
  border: solid 5px silver;
/*   overflow: hidden; */
}
#c1 {
  float: left;
  width: 50px;
  height:20px;
  background-color: blue;
}
#c2 {
  float: left;
  width: 30px;
  height:20px;
  background-color: red;
}
#c3 {
/*   float: left; */
  height:20px;
  background-color: green;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#c3不能为"float: left;", 否则显示如下.

若#c3为"float: left;", 即使#p为"overflow: hidden;"也不能强制#c3不换行.