一位哥伦比亚学者在“纪念美洲发现——两个世界汇合500周年国际学术讨论会上”说，“黄金和白银的作用只是使两个大陆之间的距离更加遥远了”。由此可知（    ）

$①$ 画射线DA；

$②$ 画直线CD；

$③$ 连结AB、BC；

$④$ 延长BC，交射线DA的反向延长线于E．

如图，EFGH为矩形台球桌面，现有一白球A和一彩球B.应怎样击打白球A,才能使白球A碰撞台边EF,反弹后能击中彩球B?通过作图，指出A球运行路线.

注意：1).词数100左右；

2).可适当增加细节，以使行文连贯；

Dear Li Hua,

    As a freshman in high school,I badly need your help with my sleep problem.The school rule goes that for every dormitory（宿舍）,students are only allowed（被允许）to keep the lights on before 10:40 p.m.So we should all go to bed after 10:40.However,one of my roommates（室友）often washes her clothes as late as 11:00 p.m.,and some others even turn on their flashlights（手电筒）to do homework.The noise and the light really make it hard for me to fall asleep（入睡）,I want to tell them to stop it,but I worry it will harm our relationships.What should I do?

Yours,

Sarah