It is really _____ useful dictionary, ______ dictionary every one of us needs．
| A．an, a | B．a, the | C．the, a | D．a, a |
Is this the factory______ he worked ten years ago?
| A．that | B．where |
| C．which | D．whom |
______ entering the room, she opened her bag to review lessons.
| A．Since | B．Only |
| C．Unless | D．Upon |
This is the reason ______he explained at the meeting for his carelessness in his work.
| A．that | B．what | C．how | D．why |
______ is a waste of time spending many hours ______ computer games every day.
| A．It; to play | B．That; to play |
| C．It; playing | D．That; playing |
He is a man of great experience ______ we can learn a lot.
| A．who | B．that |
| C．from which | D．from whom |