請教加拿大移民問題。

我申請移民有一段時間了。前一陣子給buffalo發信。回信兩次都是這個

We have requested background information from other government offices(s). Unfortunately, we cannot respond to requests for the status of your application before this information is received.

請問他們在查什麽，聽說幾千人裏才5－6個查background.我不會是中了吧？如果中了，通過幾率有多少呢？thanks