用古诗文原句填空。
①                 ，志在千里。（曹操《龟虽寿》）
②衣带渐宽终不悔，                 。
③无可奈何花落去，                 。（晏殊《浣溪沙》）
④无言独上西楼，月如钩，                        。（李煜《相见欢》）
⑤岑参《白雪歌送武判官归京》一诗中，词尽而意不尽，余味绵绵，最能表达依恋簿、不舍之情的一句          ，        。
⑥范仲淹《岳阳楼记》一文中表明自己“进”“退”皆忧思想的句子是：“                        ，                     。”

A: Good morning， Zhou Jun.____

B: I usually come to school on foot.

A:____

B: Six. I have four classes in the morning and two classes in the afternoon.

A:____

B: My favorite sport is basketball.

A:____

B: Because it's very exciting(令人兴奋的).

A:____

B: Mr. Zhao. Look! He is playing basketball there.

A: Nice talking to you. Thank you.

（Ⅰ）证明：PB∥平面AEC；

（Ⅱ）设二面角D﹣AE﹣C为60°，AP=1，AD= $\sqrt{3}$ ，求三棱锥E﹣ACD的体积．