阅读理解

    Hi, I'm Mo Hongwei from Changsha, Hunan. I'm going to enjoy myself during the New Year holiday. On 1st January, I'm going to stay at home and do my homework. On the morning of 2nd January, I'm going to meet my grandfather's friend Mr. Smith at the train station. In the afternoon, I'm going to take Mr. Smith around my school. In the evening, we're going to have a welcome party for him. On the morning of 3rd January, I'm going to ask Mr. Smith to teach me to write with the left hand. And I'm going to ask him to give me some advice(建议) about reading. I think my New Year holiday is going to be fun.

 用天平和量筒测量形状不规则小石块的密度，下列步骤不需要的是（　　）

李华的爸爸患了肝炎，医生建议他要少吃富含（    ）的食物．

如图，已知AE与BF相交于点D，AB⊥AE，垂足为点A，EF⊥AE，垂足为点E，点C在AD上，连接BC，要计算A、B两地的距离，甲、乙、丙、丁四组同学分别测量了部分线段的长度和角的度数，各组分别得到以下数据：

甲：AC、∠ACB；  乙：EF、DE、AD；  丙：AD、DE和∠DCB；   丁：CD、∠ABC、∠ADB．

其中能求得A、B两地距离的数据有（　　）