教学研究
参考答案：是人们有意识、有目的、有计划地主动探索自然界客观规律性的一种特殊的认识和实践活动。
用白纸剪一些边长相同的正三角形、正方形、正五边形、正六边形．用信封A装若干个正三角形、信封B装若干个正方形、信封C装若干个正五边形、信封D装若干个正六边形．将信封A、B、C、D（信封的大小、颜色、质地完全相同）装入不透明的袋子中．
（1）随机摸出一个信封，求该信封所装正多边形能镶嵌成一个平面图案的概率；
（2）随机摸出一个信封不放回，接着再随机摸出一个信封，求同时用这两次摸出信封中的两种正多边形能镶嵌成一个平面图案的概率？（用列表法或树形图法解答）
A woman tells the nurse that her 6-year-old daughter has severe nosebleeds. Which of the following instructions should the nurse give this woman to manage nosebleeds
A．Help the child assume a comfortable position with her head tilted backward.
B．Tilt the child's head backward and place firm pressure on the nose.
C．Help the child lie on her stomach and collect the blood on a clean towel.
D．Place the child in a sitting position with her neck bent forward and apply firm pressure on the nasal septum.
