全口义齿初戴时，用双手交替加压检查，发现上颌义齿左右翘动，最常见下列哪项原因？（）

请认真阅读下面的短文，并根据短文内容回答文后的问题，将答案写在每个小题下的横线上。

     In many western schools, sports day is a big event. Children take part in competitive (竞争性的) sports,

trying to break school records and take the first place.

     Sports days, or sports meets, are usually held in the warmer seasons, either at the beginning or the end of

the school year. They are also called field days.

     Primary school sports days are fun. They usually have activities such as the egg and the spoon race and

the sack race. Other events include the skipping race (跳绳) and the three-legged race. In middle and high

schools, sports days include many of the common track and field events ( 田径项目). They are more serious

and competitive than primary school ones.

     Students' parents and other relatives also come to the school on sports days. They watch children play.

Many schools in the West have "mothers and fathers" races for parents to take part in! Although sports days

are exciting, they also have some problems. According to some reports in the US, sports days have become

too competitive to be good for students. Some parents put too much pressure ( 压力) on the children. Some

schools don't have  mothers and fathersn races any more as there is much fighting and cheating.

1. What do children try to do when they take part in sports meets?

     ________________________________________________________

2. When are sports days usually held in the school years?

    ________________________________________________________

3. What are primary school and middle school sports days like? 

    ________________________________________________________

4. Who would come to the school to watch children play on sports days? 

    ________________________________________________________

5. What does the writer think about sports days? 

    ________________________________________________________

对于弹簧储能操动机构的断路器的变配电所宜采用( )作为合、分闸操作电源。

A．220V蓄电池组

B．110V蓄电池组

C．小容量镉镍电池

D．硅整流和电容储能

1962年4月20发行的第三套人民币是我国设计、发行和流通时间最长的一套人民币。

节流阀阀口面积一经调定，通过流量即不变化。

“我感到压抑，感到窒息，我的忍耐力崩溃了，禁不住发疯似地大叫了一声，冲向大门，拼命摇着门锁。”反抗哥哥后，被关在红房子里的简爱是什么结局？她有什么变化？（）

A、疯了但更无拘无束

B、吓晕了但更坚强不屈

C、屈服并学会了虚伪逢迎