Route :: post（）显示此错误：MethodNotAllowedHttpException

Route::post() shows the following error:

MethodNotAllowedHttpException in RouteCollection.php line 219

I changed the route ::post() into get(). That's working fine, but I want to use it this way:

Route::post()

Here is my form:

<form role="form" method="post" accept="">
  <div class="form-group">
    <label for="email">Email address:</label>
    <input type="email" class="form-control" id="email">
  </div>
  <div class="form-group">
    <label for="pwd">Password:</label>
    <input type="password" class="form-control" id="pwd">
  </div>
  <div class="checkbox">
    <label><input type="checkbox"> Remember me</label>
  </div>
  <button type="submit" class="btn btn-default">Submit</button>
</form>

Here is the route:

Route::post('/posts', 'Cdesignation@index');

How can I solve this error, where is the problem?