设复数$z=\frac{1}{2}+\frac{\sqrt{3}}{2}i$，则$\frac{z}{\stackrel{-}{z}}=$（     ）

⑴Where are you?____                                                         A. I'm talking to my friend.

⑵Excuse me. Where is the supermarket, please?____        B. I'm behind the tree.

⑶Thank you.____                                                                C. Turn left.

⑷Where is the train?  ____                                                  D. It's at the station.

⑸What are you doing?____                                                E. You are welcome.

“苍天已死，黄天当立，岁在甲子，天下大吉”，打着这一口号的起义是（    ）