构成总体的所有单位至少有两个主要属性相同，这是组成总体的前提条件。( )

引起风湿病常见皮肤损害的原因是（）

A.感染

B.血管炎性反应

C.机械性损伤

D.过敏反应

E.药物反应

下列选项中哪个方法可以判断线程是否处于活动状态

A． 0 0

B． -5 0

C． -1 6

D．0 6

可在无菌条件下进行粉碎的是（）。

A.球磨机

B.柴田粉碎机

C.锤式粉碎机

D.羚羊角粉碎机

A Letter From Santa Claus

　　Dear,

　　I hope you are well and that you are looking forward to Christmas.

　　I am always very busy at this time of the year. There 小题1:______(be) so many jobs to do. I have to 小题2:______(clean) and polish the sleigh and groom the reindeer. Then there are all those presents to sort out. I hardly have time to stop for something小题3:       （eat） . Mind you, I have been trying 小题4:_____(not eat) too much. I小题5:______(begin) to get a bit too fat小题6:     （get） down some of the chimneys!!

　　Have you been busy 小题7:______(find) presents for your family?

　　What would you like to give to them? Last year I 小题8:______(receive) two hundred and fifty bottles of aftershave. I wouldn't mind, but I have a beard!

　　Do you know what you would like for Christmas? Perhaps you小题9:_____(tell) me when you write to me. I would like some warm socks and some thick gloves. It's very cold sitting on that sleigh in the middle of winter!

　　This year I have a new reindeer, I 小题10:______(not think) of a name for him yet. Do you have any ideas? I'd love to hear them if you do.

　　Well, I suppose I had better 小题11:______(get) back to work. Please 小题12:______(write) to me and tell me all about yourself and your family and your friends. I would love to hear from you.

　Merry Christmas!

　　Santa

材料一美国联邦党人当年设计政治制度的基本精神是什么呢？简单地说，就是两个字——“有衡”。政治制度的“有衡”包括两层含义：第一，不同权力之间的相互制衡；第二，不同利益之间的相互均衡。

————《论政治文明的内在灵魂》

材料二“美国实行联邦制政体——中央政府只从州政府的权力中拿走了若干明确列举的权力，州政府则保留着中央政府拿走的权力之外的所有权力》”.

材料三2008年11月5日，奥巴马正式当选为美国第44任总统。2009年1月21日，希拉里.克林顿（美国前总统克林顿的夫人）宣誓就任美国国务卿。

结合所学知识，谈谈你对材料二的理解。