# 键盘行
<p>给你一个字符串数组 <code>words</code> ，只返回可以使用在 <strong>美式键盘</strong> 同一行的字母打印出来的单词。键盘如下图所示。</p>

<p><strong>美式键盘</strong> 中：</p>

<ul>
	<li>第一行由字符 <code>"qwertyuiop"</code> 组成。</li>
	<li>第二行由字符 <code>"asdfghjkl"</code> 组成。</li>
	<li>第三行由字符 <code>"zxcvbnm"</code> 组成。</li>
</ul>

<p><img alt="American keyboard" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/10/12/keyboard.png" style="width: 100%; max-width: 600px" /></p>

<p> </p>

<p><strong>示例 1：</strong></p>

<pre>
<strong>输入：</strong>words = ["Hello","Alaska","Dad","Peace"]
<strong>输出：</strong>["Alaska","Dad"]
</pre>

<p><strong>示例 2：</strong></p>

<pre>
<strong>输入：</strong>words = ["omk"]
<strong>输出：</strong>[]
</pre>

<p><strong>示例 3：</strong></p>

<pre>
<strong>输入：</strong>words = ["adsdf","sfd"]
<strong>输出：</strong>["adsdf","sfd"]
</pre>

<p> </p>

<p><strong>提示：</strong></p>

<ul>
	<li><code>1 <= words.length <= 20</code></li>
	<li><code>1 <= words[i].length <= 100</code></li>
	<li><code>words[i]</code> 由英文字母（小写和大写字母）组成</li>
</ul>

<p>以下错误的选项是？</p>
## aop
### before
```cpp

```
### after
```cpp

```

## 答案
```cpp

```
## 选项

### A
```cpp

```

### B
```cpp

```

### C
```cpp

```
