只有自带的应用中心能打开，ubuntu应用中心闪退，求解！

这是执行sudo software-center时的错误代码：
ERROR:root:DebFileApplication import
Traceback (most recent call last):
File "/usr/share/software-center/softwarecenter/db/__init__.py", line 6, in <module>
from .debfile import DebFileApplication, DebFileOpenError
File "/usr/share/software-center/softwarecenter/db/debfile.py", line 25, in <module>
from softwarecenter.db.application import Application, AppDetails
File "/usr/share/software-center/softwarecenter/db/application.py", line 28, in <module>
import softwarecenter.distro
File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 201, in <module>
distro_instance = _get_distro()
File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 176, in _get_distro
module = __import__(distro_module_name, globals(), locals(), [], level)
ImportError: No module named "elementary"
Traceback (most recent call last):
File "/usr/sbin/update-software-center", line 38, in <module>
from softwarecenter.db.update import rebuild_database
File "/usr/share/software-center/softwarecenter/db/update.py", line 33, in <module>
from softwarecenter.backend.scagent import SoftwareCenterAgent
File "/usr/share/software-center/softwarecenter/backend/scagent.py", line 30, in <module>
from softwarecenter.distro import get_distro, get_current_arch
File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 201, in <module>
distro_instance = _get_distro()
File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 176, in _get_distro
module = __import__(distro_module_name, globals(), locals(), [], level)
ImportError: No module named "elementary"