阅读上面短文，然后判断句子正( A )误( B)。
     A man saw a boy standing beside a lake with a mirror (镜子).“Excuse me,” he said, “but could you tell me what you're doing?”
   “I'm fishing.”
   “With a mirror? Could you tell me how it works?”the man asked.
   “OK, but I want five dollars.”
     The man wanted to know the secret very much, so he handed the boy the money.“Now show me how it works,” he said. “Well”, the boy began, “you hold (拿) the mirror towards the water, and when a fish goes by, the sunlight in the mirror gives him a surprise. He stops and doesn't know what to do, and then you catch him at once. ”The man was surprised, “Can you really catch fish with the mirror? How many did you catch?”
   “You're the fifth today!” replied the boy.

若cosα=$\frac{2}{3}$，α是第四象限角，求$\frac{\sin \left(\kappa -2\mathrm{\pi }\right)+\sin \left(\alpha -3\pi \right)\cos \left(\alpha -3\pi \right)}{\cos \left(\mathrm{\pi }-\mathrm{\alpha }\right)-\cos \left(\mathrm{\pi }-\mathrm{\alpha }\right)\cos \left(\alpha -4\pi \right)}$的值．

如图，将一副三角尺按不同位置摆放，摆放方式中∠α与∠β互余的是（   ）

表示阿伏加德罗常数的值。下列说法正确的是

—Are ____Jill?

—No, I'm not. I'm her sister．