问题
选择题
如图，水平支持面上的滑块M在水平拉力F作用下保持静止，现保持F的大小及其作用点O不变，令F在竖直面内缓慢地顺时针旋转45°，则以下选项中正确的是
A．M所受的合力仍为零
B．M将处于超重状态
C．M与地面间的摩擦力将增大
D．M对地面的压力将大于地面对它的支持力
答案
答案：A
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如图，水平支持面上的滑块M在水平拉力F作用下保持静止，现保持F的大小及其作用点O不变，令F在竖直面内缓慢地顺时针旋转45°，则以下选项中正确的是
A．M所受的合力仍为零
B．M将处于超重状态
C．M与地面间的摩擦力将增大
D．M对地面的压力将大于地面对它的支持力
答案：A
Working parents feel that they are not giving their children enough care. They think that their children feel 1 and 2 to spend more time with them. Scientists in some colleges have found that working parents believed that they knew 3 their children, but 4 had ever asked their children what they thought. So scientists interviewed (采访) over 1,000 children of working mothers or fathers to 5 what they wanted. They asked the children 6 they wanted their parents to stay 7 and some 8 questions．After they collected the answers, it was 9 that only 10% of the children in their study said that they wanted more time with their parents. _10_, the children who were interviewed said they wanted their parents to give more 11 to them. They said that their parents were as 12 as a bee. When they were asked about what they 13 most, a large number of the children said that they wanted to feel important and 14 . So parents should know what their children really want and how to get along 15 with them.
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