方法-1：使用text-overflow: ellipsis;

span {
    white-space: nowrap;
    text-overflow: ellipsis;
    width: 250px;
    display: block;
    overflow: hidden
}

<span>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</span>

方法-2：使用-webkit-line-clamp

p {
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical; 
}

<p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>

没有 flexbox 的解决方案

设置文本容器的高度，并相应地使用 webkit-line-clamp。

.line-clamp-3 {
  display: block;
  display: -webkit-box;
  height: 50px;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  text-overflow: ellipsis;
}

Text will be shown like this.

带有 flexbox 的解决方案

您也可以从以下链接获取帮助：https://css-tricks.com/flexbox-truncated-text/

.flex-parent {
  display: flex;
}
.short-and-fixed {
  width: 30px;
  height: 30px;
}
.long-and-truncated {
  margin: 0 20px;
  flex: 1;
  min-width: 0;
}
.long-and-truncated span {
  display: inline;
  -webkit-line-clamp: 3;
  text-overflow: ellipsis;
  overflow: hidden;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  word-wrap: break-word;
}

<div class="flex-parent">
  <div class="flex-child short-and-fixed">
  </div>
  <div class="flex-child long-and-truncated">
    <span>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</span>
  </div>
  <div class="flex-child short-and-fixed">
  </div>
</div>