骨骼都有最适宜的应力范围,下列哪项不会导致骨钙吸收加快
A.应力过高
B.应力过低
C.慢跑
D.长期卧床
E.失重
参考答案:C
如下图是甲、乙两个电阻的电流I与电压U的关系图象,将它们并连接入电路,下列说法正确的是( )
A.通过甲的电流大于通过乙的电流
B.通过甲的电流小于通过乙的电流
C.甲、乙并联的总电阻随它们两端电压的升高而减小
D.甲、乙并联的总电阻随它们两端电压的升高而增大
Recently, I flew to Las Vegas to attend a meeting. As we were about to arrive, the pilot announced with apology that there would be a slight (16) before setting down. High desert winds had (17) the airport to close all but one runway. He said that we would be (18) the city for a few minutes waiting to (19) . We were also told to remain in our seats meanwhile with our seat belts fastened (20) there might be a few bumps(颠簸). Well, that few minutes turned into about four-five minutes, including a ride that would make a roller coaster(过山车) (21) by comparison. The movement was so fierce that several passengers felt (22) and had to use airsickness bags. As you might guess, that’ s not a good thing to have happen in a(n) (23) space because it only (24) to increase the discomfort of the situation.
About twenty minutes into the adventure, the entire airplane became very (25) There was now a sense of anxiety and fear that could be (26) noticed. Every passenger simply held on for dear life …except one. A (27) was having a good time! With each bump of the (28) , he would let out a giggle (咯咯地笑)of delight. As I observed this, I (29) that he didn’t know he was supposed to be afraid and worried about his (30) . He neither thought about the past nor about the future. Those are what we gown--ups have learned from (31) . He was (32) the ride because he had not yet been taught to fear it. Having understood this, I took a deep breath and (33) back into my seat, pretending I was (34) on a roller coaster. I smiled for the rest of the flight. I even (35) to giggle once or twice, much to the chagrin(随恼) of the man sitting next to me holding the airsickness bag.
31()
A.pilot
B.baby
C.guard
D.man