（1）使用float
<div class="use-float">
<div></div>
<div></div>
</div>
.use-float>div:first-child{
width:100px;
float:left;
}
.use-float>div:last-child{
overflow:hidden;
}
（2）使用table
<table class="use-table">
<tr>
<td></td>
<td></td>
</tr>
</table>
.use-table{
border-collapse:collapse;
width:100%;
}
.use-table>tbody>tr>td:first-child{
width:100px;
}
（3）用div模拟table
<div class="use-mock-table">
<div></div>
<div></div>
</div>
.use-mock-table{
display:table;
width:100%;
}
.use-mock-table>div{
display:table-cell;
}
.use-mock-table>div:first-child{
width:100px;
}
（4）使用flex
<div class="use-flex">
<div></div>
<div></div>
</div>
.use-flex{
display:flex;
}
.use-flex>div:first-child{
flex:none;
width:100px;
}
.use-flex>div:last-child{
flex:1;
}
