焊媒的特点是（） A.流动性好 B.强度很差 C.易被腐蚀 D.熔点较高 E.价格昂

如图所示，光滑水平面上放置一条形磁铁，小铁球在运动过程中由于受到磁铁的吸引而做曲线运动，请你说明小铁球做曲线运动的原因是：______．

单词拼写。

1. Two guards are standing there to look after the _________ (安全) of those personal possessions.

2. You have to make sure about the _________ (分配；分发) of these goods to each house.

3. This project is _________ (运作) very well-more and more children are getting what they need.

4. We're concerned about the fate of the _________ (代替) teachers.

5. Don't worry. It's just a r_________ (例行的) medical examination.

金属烤瓷冠瓷层热膨胀系数的特点是

A．随着烧结次数增加而提高
B．随着烧结次数的增加而降低
C．与烧结的次数无关
D．与烧结的时间无关
E．与金属材料无关

男，22岁，血压143／90mmHg，大量尿蛋白，血浆清蛋白25g／L。下列何种疾病可能性大（ ）

A．隐匿性肾炎

B．高血压肾小动脉硬化

C．急性肾炎

D．肾病综合征

E．慢性肾炎

常见的语法范畴是（）等。