（Ⅰ）求椭圆 $C$ 的方程；

（Ⅱ）过点 $\left(1,0\right)$ 的直线 $l$ 交椭圆于 $B,D$ 两点，设直线 $AB$ 斜率为 $k_1$ ，直线 $AD$ 斜率为 $k_2$ ，求证： $k_1{k}_2$ 为定值.

根据短文内容选择正确答案。

    Mrs. Smith is Jim's mother. She loves her family very much.  She goes to the store every day. She often buys food, fruit and clothes for Jim and her husband. Now many clothes are on sale at Renmin Clothes Store. They are very cheap. Mrs. Smith comes to the store and she wants to buy some clothes for her family. There they have sweaters in all colors for ￥15 each and sports shoes for only ￥28. Mrs. Smith likes the red sweater and she buys one for herself. She buys a pair of sports shoes for her son. The great T-shirts in the store are just ￥18!  She buys a white one for Mr. Smith. And that's not all. The socks, in all colors, are ￥2 each. She buys the socks in many colors for her family. She is really a Rood mother and a good wife (妻子).

要学好初中各门功课，我们必须（    ）
①课前认真预习，开展各种准备活动                  ②课堂上专心听讲，认真做好笔记
③课后及时巩固复习，独立认真完成作业          ④平时学不学都没有关系，只要考试前认真复习就行了