Django 表单 POST CSRF verification failed. Request aborted.错误

<form method="post">
　　{% csrf_token %}
    {{form.as_p}}
    <input type="submit" name="ok">
</form>

from django.shortcuts import render_to_response, RequestContext
from django.http import HttpResponse
from appA.models import *
from appA.forms import *

def hello(request):
    if request.method ==‘POST‘:
        form = Mybook(request.POST)
        if form.is_valid():
            data = form.cleaned_data
            name = data[‘name‘]
        return HttpResponse(name)

    form = Mybook()
    return render_to_response(‘h1.html‘,{‘form‘:form},context_instance=RequestContext(request))