问题
单项选择题
一个数列为1，-1，2，-2 ，-1，1，-2，2，1，-1，2，-2……．则该数列的第2009项为()
A．-2
B．-1
C．1
D．2
答案
参考答案：C
解析： 2009/8=251余数1，选C。
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一个数列为1，-1，2，-2 ，-1，1，-2，2，1，-1，2，-2……．则该数列的第2009项为()
A．-2
B．-1
C．1
D．2
参考答案：C
解析： 2009/8=251余数1，选C。
| 交际问答(从B栏中找到相应的答案) | |
| A ( )1. Where is your teacher? ( )2. What's this? ( )3. Whose books are these? ( )4. Who's on duty today? ( )5. What's her name? ( )6. Which car is Mr. Green's? ( )7. What colour are the flowers? ( )8. What can you see on the hill? ( )9. How old is your friend? ( )10. Is it a Chinese car? | B A. It's a clock. B. They are theirs. C. She's in the classroom. D. The red one is his. E. They are yellow. F. Her name's Wei Hua. G. She's thirteen. H. Yes, it is. I. I am. J. I can see some flowers. |