Fred entered without knocking and, very out of breath, sank _______ a chair.
------Have you known each other for long? ------ Not very, ________we started to work in the ABC Motor Company.
According to the rules, students ______ get grades not lower than 85% in any subject in order to get the scholarship.
The young scientist has made such great achievements in his chosen field ______ nobody else can make.
We were told not to touch the equipment in the laboratory unless ________.
------Where did you first meet your boyfriend? ------It was in the department store ______ he worked.