①维生素C能促进人体生长发育．下列富含维生素C的是____（填字母）．

A．牛肉    B．辣椒   C．鸡蛋

②缺乏某种微量元素将导致甲状腺肿大，且造成智力损害，该微量元素是____

A．碘    B．铁     C．钙

④使用青霉素可能会产生过敏，在用药前患者一定要进行____．

   Many people don’t think that the number 13 is a lucky number. Many hotels do not have a 13th floor. The floors go from 12 to 14, and there is no number13. Some people will never sit at a table with 12 other people. They will tell someone to go or ask another person to sit with them.
No one really knows why people do not like the number 13. Perhaps one reason is that when people began to count, they used ten fingers and two hands. This made 12. They could not count more.
   Some Christians (基督徒) say that 13 is not lucky because there were 13 people at a meal the day before Jesus (耶稣) was killed (被杀). In a story about the old Greek (希腊的) gods, 12 gods were asked to a meal but one more came. This made 13. It is why the god Balder, who was at the meal, was killed.

如图，市政府准备修建一座高AB=6m的过街天桥，已知天桥的坡面AC与地面BC的夹角∠ACB的正弦值为$\frac{3}{5}$，则坡面AC的长度为（　　）m．

根据《自治区少数民族学前和中小学双语教育2010至2020年发展规划》规定，到2020年，接受双语教育的少数民族中小学生占少数民族中小学生的90%以上，其中义务教育阶段达到95%左右。这一举措有利于（    ）