尝试使用时出现此错误apt-get：
E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?
我怎样才能解决这个问题？
我试过这个：
moncef@moncef-Latitude-E7270:~$ sudo apt install tor
Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 3321 (apt)
Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 3321 (apt)
Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 3321 (apt)
Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 3321 (apt)
Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It …