房性期前收缩的心电图特点是（） A.代偿间歇不完全 B.可见逆行性P′波 C.T波方

Sport is not only physically challenging, but it can also be mentally challenging. Criticism from coaches, parents, and other teammates, as well as pressure to win can create an excessive amount of anxiety or stress for young athletes(运动员). Stress can be physical, emotional, or psychological and research has indicated that it can lead to burnout. Burnout has been described as dropping or quitting of an activity that was at one time enjoyable.

　　The early years of development are critical years for learning about oneself. The sport setting is one where valuable experiences can take place. Young athletes can, for example, learn how to cooperate with others, make friends, and gain other social skills that will be used throughout their lives. Coaches and parents should be aware, at all times, that their feedback to youngsters can greatly affect their children. Youngsters may take their parents' and coaches' criticisms to heart and find a flaw (缺陷) in themselves.

　　Coaches and parents should also be cautious that youth sport participation does not become work for children. The outcome of the game should not be more important than the process of learning the sport and other life lessons. In today's youth sport setting, young athletes may be worrying more about who will win instead of enjoying themselves and the sport. Following a game many parents and coaches focus on the outcome and find fault with youngsters' performances. Positive reinforcement should be provided regardless of the outcome. Research indicates that positive reinforcement motivates and has a greater effect on learning than criticism. Again, criticism can create high levels of stress, which can lead to burnout.

小题1:An effective way to prevent the burnout of young athletes is ______

A．to reduce their mental stress

B．to increase their sense of success

C．to make sports less competitive

D．to make sports more challenging小题2:According to the passage sport is positive for young people in that ____ .

A．it can help them learn more about society

B．it enables them to find flaws in themselves

C．it can provide them with valuable experiences

D．it teaches them how to set realistic goals for themselves小题3:Many coaches and parents are in the habit of criticizing young athletes ______ .

A．believing that criticism is beneficial for their early development

B．without realizing criticism may destroy their self confidence

C．in order to make them remember life's lessons

D．so as to put more pressure on them小题4:According to the passage parents and coaches should _____________ .

A．pay more attention to letting children enjoy sports

B．help children to win every game

C．train children to cope with stress

D．enable children to understand the positive aspect of sports小题5:The author's purpose in writing the passage is ____________ .

A．to teach young athletes how to avoid burnout

B．to persuade young children not to worry about criticism

C．to stress the importance of positive reinforcement to children

D．to discuss the skill of combining criticism with encouragement

学校管理的目标和尺度是（）。

检查轨道线路质量时，接头平整度轨面及内侧差错不大于（）。

A、8mm

B、4mm

C、2mm

D、6mm

炉原料粒度对高炉冶炼有什么影响？

不同通信系统有源设备应满足相应的（）、（）等指标，并在不同应用情况下，选择不同指标的设备。

A.带宽要求

B.频段要求

C.上行增益要求

D.杂散、互调抑制

E.下行增益要求