【简答题】如图,点A 1 ,A 2 ,A 3 ,A 4 ,…,A n 在射线OA上,点B 1 ,B 2 ,B 3 ,…,B n―1 在射线OB上,且A 1 B 1 ∥A 2 B 2 ∥A 3 B 3 ∥…∥A n ﹣1 B n ﹣1 ,A 2 B 1 ∥A 3 B 2 ∥A 4 B 3 ∥…∥A n B n ﹣1 ,△A 1 A 2 B 1 ,△A 2 A 3 B 2 ,…,△A n ﹣ 1 A n B n...
【简答题】C While they were almost unknown twenty years ago, it seems that mobile phones these days are part of everyone’s life. However, as with other inventions such as the television and the computer, they a...