10岁男孩，1年来时有尿频、尿急、尿痛和排尿困难、尿流中断，改变体位后又能继续排尿，

患者，男，5岁，前牙反，后牙近中错，反覆深，反覆盖小，牙齿无松动，牙列整齐，不伴拥挤。

乳牙期矫治的目的（）

A.促进上颌发育，抑制下颌过度发育

B.抑制上颌发育

C.美观要求

D.促进下颌发育

E.以上都不是

关于体层摄影叙述错误的是（）

A.曝光角是连杆摆过的角度

B.影像被模除的程度与曝光角无关

C.体层运动的轨迹有圆、矩形、椭圆等

D.具有两种以上轨迹的称为多轨迹体层

E.曝光角越大，照片上清晰影像对应的厚度越小

填空题。

     Keeping in touch with our friends is an important part of friendship. This does not mean that   1  have

to write or call our friends every day. It does mean, however, that we   2  care enough about our friends

to find out how they are doing from time to time.

     People have different habits about keeping in touch with others. Some like to call their friends,

sometimes many times   3  a day. Others prefer to e-mail their friends. Still   4    prefer writing letters so

that they can include photos or interesting articles  5  the envelopes along with their letters. Some even

write postcards while they are on vacation  6  send them to friends.

     Every kind of communication is important. It is   7  important what kind of call we make or letter we

send.   8  is important is that we let others know we care about them.

塑性变形是指排土场（），而部分岩土连续下滑。

第二批教育实践活动的基本原则是什么？