—Amy, please tell the people ______ for their turns to come to my office five minutes later.
— Yes, sir.
| A．wait | B．waited | C．waiting | D．to wait |
I feel greatly honored ____ into their society.
| A．to welcome | B．welcoming | C．to be welcomed | D．welcomed |
In his book,he explains both ______ it means to be a scientist and ______ science works.
| A．how; how | B．what; that |
| C．what; how | D．how; that |
The great scientist became world-known in the early 1970s,______ he and another scientist made new discoveries about black holes.
| A．which | B．where | C．when | D．then |
______ giving up, he went on with his research,got his PhD and married the girl.
| A．Without | B．Except | C．Instead of | D．But for |
Think twice before you make a decision on this matter. It will make ______ to your life.
| A．no difference | B．a difference | C．little difference | D．difference |