如图，在已知的△ABC中，按以下步骤作图：

若CD=AC，∠A=50°，则∠ACB的度数为　____ °．

①分别以B，C为圆心，以大于$\frac{1}{2}$BC的长为半径作弧，两弧相交于两点M，N；

②作直线MN交AB于点D，连接CD．

材料一：砥砺奋进铸辉煌，同心共筑中国梦！党的十九大报告全面总结了过去五年来辉煌成就：我国经济建设取得重大成就。全面深化改革取得重大突破。中国特色社会主义制度更加完善，国家治理体系和治理能力现代化水平明显提高，全社会发展活力和创新活力明显增强。民主法治建设迈出重大步伐。思想文化建设取得重大进展。思想文化建设取得重大进展。生态文明建设成效显著。强军兴军开创新局面。港澳台工作取得新进展。全方位外交布局深入展开。全面从严治党成效卓著。

材料二：青年有理想，国家有力量！******在十九大报告中对青年一代提出了殷切期望：青年一代有理想、有本领、有担当，国家就有前途，民族就有希望。中国梦是历史的、现实的，也是未来的；是我们这一代的，更是青年一代的。中华民族伟大复兴的中国梦终将在一代代青年的接力奋斗中变为现实。

“党的十九大精神进校园”宣讲活动正在进行，请你参与并完成如下任务：

    My name is Jim. My favorite day is October 18th, because it's my birthday. I am very happy on that day. I eat eggs for breakfast. Then my friends come to my home and play with me. We sing and dance. Someone plays the piano and someone plays the guitar. Lunch is very nice. After lunch, my parents take me to see a movie. My favorite movies are action movies(动作片). After supper, my parents, my sister and I watch TV. Then I go to bed at ten thirty. I don't do my homework on that day. I am very tired but happy on my birthday.

I have a good chance ____ (visit) Shanghai this summer holiday.