在一次设备上可采取什么措施来提高系统的稳定性？

第一期乳癌的肿块直径不超过（）

A.5cm

B.4cm

C.3cm

D.2cm

E.1cm

阅读理解。

根据短文内容,从选项中选出能填入空白处的最佳选项.选项中有两项为多余选项。

     Recently some American scientists have given a useful piece of advice to people in industrialized

nations. They say people should eat more of the same kind of food eaten by humans living more than

10,000 years ago.   1  

     The scientists say that the human life has changed greatly. Our bodies have not been able to deal

with these changes in lifestyle and this had led to new kinds of sicknesses.    2   So they are called

"diseases of civilization". Many cancers and diseases of the blood system are examples of such

diseases.

     Scientists noted that people in both the Old Stone Age and the New Stone Age enjoyed very

little alcohol or tobacco, probably none.   3  However, a change in food is one of the main differences

between life in ancient times and that of today.

     Stone Age people hunted wild animals for their meat, which had much less fat than domestic ones.

They ate a lot of fresh wild vegetables and fruits. They did not have milk or any other dairy products,

and they made very little use of grains.   4  We eat six times more salt than our ancestors. We eat

more sugar. We eat twice as much fat but only one third as much protein and much less vitamin C.

        5  But scientists say that we would be much healthier if we eat much the same way the ancient

people did, cutting the amount of fatty, salty and sweet food.

A. Stone Age people lived a simple life.

B. But today, we enjoy eating a lot of these.

C. In that case, they would live much healthier.

D. Ancient people also got lots of physical exercise.

E. These new sicknesses were not known in ancient times.

F. People today probably don't want to live like our ancestors.

G. Modern people used to suffer from "diseases of civilization".

患者女性，30岁，尿毒症，出现胸痛，心包摩擦音。

心包摩擦音听诊的特点不包括

A．在心前区最响亮

B．坐位前倾更明显

C．吸气末更明显

D．与心搏一致

E．屏气时仍存在

水准仪的基本组成包括( )。

A．照准部、水平度盘和基座三部分

B．照准部、水准器和基座三部分

C．望远镜、水准器和基座三部分

D．望远镜、水平度盘和基座三部分

消息的背景材料中，关于时代政治背景、国际形势、社会条件等背景材料，称为( )

A．时代背景

B．国际背景

C．社会背景

D．政治背景