A )信息归纳：阅读下面的短文,根据短文内容完成信息卡。
In 1945，6 planes and 17 men disappeared without a sign, all in one day. This was Flight 19. Flight 19's captain was Lieutenant Charles Taylor. Flight 19 was a usual flight. It took off at about 2:10 p.m. from Miami. The weather was very normal on that December 5th of 1945. A message was received at 4：00 p．m.that told about pilot Taylor not knowing the way to go because his compass(指南针) was running around and around.
After that，it was never heard from again.While searching for it，a search plane was also lost.The search for the both continued until December 10th of that same year.None of the things from Flight 19's planes，or from the search plane，was ever found.It is one of the most infamous disappearances. Searching for Flight 19 lasted five days，and covered 380，000 square miles. Dr. Kripke suggests that the accident happened because of a vortex(涡流).
Information Card
The time when the accident took place | ____. |
Flight 19's captain | ____. |
The weather on that December 5th of 1945 | ____. |
The time of searching for Flight 19 lasted | ____. |
In Dr. Kripke's opinion, the reason of the accident | ____. |
的前4项依次是20，11，2，－7的一个通项公式是（ ）