下面的代码打开yahoo.com首页，并输出p标签中的所有文字

import urllib.request
import lxml.html
chaper_url="https://www.yahoo.com/"
headers = {'User-Agent':'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0'}
req = urllib.request.Request(url=chaper_url, headers=headers)
myString=urllib.request.urlopen(req).read()
root=lxml.html.document_fromstring(myString)
txt=root.xpath("//p")
for etxt in txt:
    print(etxt.text_content())
    

换个目标： http://www.seek68.cn/bdhxqkml...
同样的代码结构

import urllib.request
import lxml.html
chaper_url="http://www.seek68.cn/bdhxqkml-7.htm"
headers = {'User-Agent':'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0'}
req = urllib.request.Request(url=chaper_url, headers=headers)
myString=urllib.request.urlopen(req).read()
root=lxml.html.document_fromstring(myString)
txt=root.xpath("//p")
for etxt in txt:
    print(etxt.text_content())
    
    

上面的代码会卡死在 myString=urllib.request.urlopen(req).read()
为何？