<form> <label for="username">用户名:</label>
<input type="text" id="username" name="username">
<label for="password">密码:</label> <input type="password" id="password" name="password">
<label for="gender">性别:</label> <input type="radio" id="male" name="gender" value="male">
<label for="male">男</label>
<input type="radio" id="female" name="gender" value="female">
<label for="female">女</label>
<label for="interests">兴趣:</label> <input type="checkbox" id="reading" name="interests" value="reading"> <label for="reading">阅读</label> <input type="checkbox" id="music" name="interests" value="music"> <label for="music">音乐</label>
<label for="city">城市:</label>
<select id="city" name="city"> <option value="beijing">北京</option> <option value="shanghai">上海</option>
<option value="guangzhou">广州</option> </select>
</form>表示一个包含文本输入框、密码输入框、单选框、复选框和下拉列表框的表单。