Original code:
<textarea class="form-control" id="addIntroduction" name="addIntroduction" row="6"
placeholder="请输入教师介绍">
</textarea>
Solution: Remove <textarea>
the newline of the label
<textarea class="form-control" id="addIntroduction" name="addIntroduction" row="6" placeholder="请输入教师介绍"></textarea>