The government of the United States began at once to investigate the case ______ a lot of students were killed.
| A．that | B．when | C．where | D．why |
17. One of the mottos for the park makes_____clear that science and business can and must work together to build the future.
| A．them | B．it | C．us | D．This |
16. This experiment turned out to be____failure, but, as we know, success often comes after___failure.
| A．a; \ | B．a; a | C．\; \ | D．\; a |
15. It is often said that the joy of travelling is________in arriving at your destination___in
the journey itself.
| A．\; but | B．\; or | C．not; or | D．not; but |
14. – How often do you go swimming?
--___________, but usually twice a week.
| A．I’m all right | B．It depends | C．With pleasure | D．I’d rather stay at home |
13. – Why does he look so worried?
-- His dad got_________in an accident.
| A．to be hurting | B．hurt | C．hurting | D．to hurt |