利用xpath建标签树以后，虽然提高了元素匹配效率，但是etree会把中文转为ASCII码，所以简单地tostring以后会有乱码。

解决方法：

import requestsfrom requests.exceptions import RequestExceptionfrom lxml import etreeheaders = {    'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0.2 Safari/605.1.15',}def get_one_page(url, headers):    try:        response = requests.get(url, headers=headers)        if response.status_code == 200:            response.encoding = response.apparent_encoding            return response.text        return None    except RequestException:        return Nonetree = etree.HTML(html)aim = tree.xpath(exp)for i in aim:    content = etree.tostring(i, encoding='utf-8', pretty_print=True, method="html").decode('utf-8')