读句子，选择合适的答句。

(____) 1. Where is the art room?

(____) 2. Is it on the second floor?

(____) 3. How many students?

(____) 4. Is this your computer room?

(____) 5. Do you have an art room?

A. It's on the first floor.

B. Forty-five students.

C. No, it isn't.

D. Yes, it is my computer coom.

E. Yes, we do.

    Mrs. Green doesn't like sports. She has much work to do at home. Her mother is coming this afternoon and she goes to meet her. Near the school she looks at her watch. She has some time. So she goes into the school. Her son isn't in the classroom. She asks a boy and knows they're behind the school. She sees some boys playing there. Her son is there too. She watches them playing and soon she's angry. She takes her son to the wall. “Go home with me, Richard.” She says, "Don't play with them. I can buy a nice ball for you. Then you don't need to scramble for the ball."

（Ⅰ）证明：BC₁∥平面A₁CD；

（Ⅱ）设AA₁=AC=CB=2，AB=2 $\sqrt{2}$ ，求异面直线BC₁与A₁D所成角的大小．

下列各项，可以作为大陆漂移假说证据的是                                     (    )
①世界一些地方的大陆轮廓的凹凸十分吻合 ②非洲和南美洲生活着不会飞的同种
海牛和鸵鸟  ③喜马拉雅山原是一片汪洋大海  ④地球上七分海洋三分陆地

2012年国际田联110m栏比赛中，刘翔以12秒97破赛会记录夺得冠军．如图所示是刘翔在跨栏时的情景，若说赛场的主席台是运动的，所选的参照物是（　　）

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