下列命题不正确的是（ ）
A．如果一个平面内的一条直线垂直于另一个平面内的任意直线，则两平面垂直
B．如果一个平面内的任一条直线都平行于另一个平面，则两平面平行
C．如果一条直线和一个平面平行，经过这条直线的平面和这个平面相交，那么这条直线和交线平行
D．如果两条不同的直线在一平面内的射影互相垂直，则这两条直线垂直
如果一个平面内的一条直线垂直于另一个平面内的任意直线，
由线面垂直的定义，可得该直线与另一个平面垂直，
由面面垂直的判定定理我们可得两平面垂直，故A正确；
如果一个平面内的任一条直线都平行于另一个平面，
则存在两条相交直线与另一个平面平行，
由面面平等的判定定理得两平面平行，故B正确；
如果一条直线和一个平面平行，
经过这条直线的平面和这个平面相交，
由线面平行的性质定理，那么这条直线和交线平行，故C正确；
如果两条不同的直线在一平面内的射影互相垂直，
则这两条直线可能垂直，也可能不垂直，故D错误
故选D
请阅读下面短文，掌握其大意，然后从36—55各题所给的A、B、C、D四个选项中，选出可以填入空白处的最佳选项。 Peer pressure can be a powerful force, and sometimes a positive one. For example, hanging out with active peers may lead kids to more, making a child’s social network a vehicle for promoting healthy habits and obesity unconsciously. The scientists studied networks of a group of students aged 5 to 12 and how the youngsters’ made and dropped friends, and effect these changing relationships had on their physical activity level. In fact, children their exercise level little by little to better those in their circle; children who with more active students were more to increase their physical activity levels, those who befriended more sedentary(久坐不动的) children became active. The children were mirroring, following or adjusting to be to their friends before they knew it. The encouraging suggest a potentially effective way to change children’s behavior. relying only on organized exercise programs to get moving, perhaps introducing sedentary kids to more active ones — might help more kids the couch. It’s believed that this is a possible novel approach to obesity . The social environment does carry more power than we have given it for, so we should make use of that intentionally to influence kids. that children are increasingly connected to one another, through face-to-face interactions or virtual ones, their networks can clearly have a deep effect many aspects of their behavior-help kids in the long run by turning them into healthier adults.
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