--- When did you last see your first teacher?
--- On ______ Friday last June, at ______ celebration of her 40th year of teaching.
A．a; the B．a; a C．/; a D．/; the
Father made a promise ______ I passed the exam, he would buy me a PS4.
A．if B．that if C．whether D．that
--- Alex came back home the day before yesterday.
--- Really? Where ______ at all?
A．had he been B．has he been C．had he gone D．has he gone
The dangerous virus ______ in the next few weeks in the laboratory can cause fatal diseases.
A．studying B．studied
C．to study D．to be studied
How can you expect him to make any progress ______ you never give him a chance to have a try?
A．when B．unless C．once D．until
Getting all your teammates ______ in a game is the key to victory.
A．trapped B．settled C．stuck D．involved
