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______the zoologists tried to prove was that the photo of the South China Tiger had been staged or technologically dealt with.
| A．That | B．Why | C．Whether | D．What |
Overpopulation is a terrible threat to the human race.Yet it is probably ____ a threat to the human race than environmental destruction.
| A．no more | B．not more | C．even more | D．little more |
Ladies and gentlemen,welcome to my program.____ me this evening is Dr.Gray.
| A．To join | B．Join | C．Joined | D．Joining |
While income worry is ____ rather common problem of the aged,loneliness is another problem that ____aged parents may face.
| A．a;/ | B．the;/ | C．a;the | D．the;the |
Many people can not learn any lessons from the mistakes____they get hurt somehow.
| A．whether | B．unless | C．if | D．when |
Everyone has periods in their lives_______everything seems very hard.
| A．when | B．where | C．which | D．that |