def questions(self):
        """获取用户的所有问题.

        :return: 用户的所有问题，返回生成器.
        :rtype: Question.Iterable
        """
        from .question import Question

        if self.url is None or self.question_num == 0:
            return
        for page_index in range(1, (self.question_num - 1) // 20 + 2):
            html = self._session.get(
                self.url + 'asks?page=' + str(page_index)).text
            soup = BeautifulSoup(html)
            question_links = soup.find_all('a', class_='question_link')
            question_datas = soup.find_all(
                'div', class_='zm-profile-section-main')
            for link, data in zip(question_links, question_datas):
                url = Zhihu_URL + link['href']
                title = link.text.strip()
                answer_num = int(
                    re_get_number.match(data.div.contents[4]).group(1))
                follower_num = int(
                    re_get_number.match(data.div.contents[6]).group(1))
                q = Question(url, title, follower_num, answer_num,
                             session=self._session)
                yield q
获取用户的所有问题.

        :return: 用户的所有问题，返回生成器.
        :rtype: Question.Iterable