明智如你，应该不会整个应用就整一个组件吧？贴心的Svelte也想到了，我们可以从其它文件中引入组件并在标签中使用它们，以此支持组合多个组件

It would be impractical to put your entire app in a single component. Instead, we can import components from other files and include them in our markup.

首先在文件App.svelte的顶部添加<script>标签并引入Nested.svelte

Add a <script> tag to the top of App.svelte that imports Nested.svelte...

<script>
	import Nested from './Nested.svelte';
</script>

<script lang="ts">
	import Nested from './Nested.svelte';
</script>

接下来就可以在标签中使用<Nested>组件了

...and include a <Nested /> component:

<p>This is a paragraph.</p>
<Nested />

注意看：虽然在Nested.svelte中也有个<p>元素但App.svelte中的样式并没有影响到它。

Notice that even though Nested.svelte has a <p> element, the styles from App.svelte don’t leak in.

为了区别于HTML原生元素，组件的标签名称采用首字母大写. [!NOTE] Component names are capitalised, to distinguish them from HTML elements.