1问题的提出例1如图1,在四棱锥P-ABCD中,底面ABCD是平行四边形,Q为AD的中点,点M在线段PC上且PM=tPC(t>0),试确定实数t的值,使得PA∥平面MQB.试题以四棱锥为载体,主要考查直线与平面平行的位置关系,以及学生的空间想象能力和推理论证能力.该题背景熟悉,立意常规,欲求结论明确,思路宽广.该题为第二学期如皋市高一期中调研测试解答题第四题,满分为15分.笔者所在 1 PROBLEM PROBLEM EXAMPLE 1 As shown in Figure 1, in the pyramid P-ABCD, the bottom surface ABCD is a parallelogram, Q is the midpoint of AD, point M is on the segment PC and PM = tPC (t> 0) the value of t, making PA∥ plane MQB. Test questions with quadrangular pyramids as the carrier, the main test straight line and the plane parallel to the positional relationship, as well as the student’s spatial imagination and reasoning ability to demonstrate the background familiar with, Wide range of ideas. The second semester of the second semester of Rugao high in the fourth quarter of the test research questions, out of 15 points.