货币的借贷、各种票据和有价证券的买卖等融资活动的场所称为( )市场。A．融资 B．

经历挫折就能走向成功。 [ ]

在网络上交换信息时对内容的“不可否认性”可通过下列______技术保证。

A．数字信封

B．公钥加密体制

C．数字签名

D．VPN

Many of us believe that a person’s mind becomes less active as he grows older. But this is not true, according to Dr Jarvik, professor of psychiatry at the University of California. She has studied the mental functioning of aging persons for several years. For example, one of her studies concerns 136 pairs of twins (双胞胎), who were first examined when they were already 60 years old. As Dr Jarvik continued the study of the twins into their 70s and 80s, their minds did not generally decline (衰弱) as was expected.

　　However, there was some decline in their psycho-motor speed. This means that it took them longer to finish mental tasks than it used to. But when speed was not a factor, they lost very little intellectual (智力的) ability over the years. In general, Dr Jarvik’s studies have shown that there is no decline in knowledge or reasoning ability. This is true not only with those in their 30s and 40s, but with those in their 60s and 70s as well.

　　It is true that older people themselves often complain that their memory is not as good as it once was. However, much of what we call “loss of memory” is not that at all. There usually was incomplete learning in the first place. For example, the older person perhaps had trouble hearing, or poor vision, or was trying to learn the new thing at too fast a speed. In the cases where the older person’s mind really seems to get worse, it is not necessarily a sign of decline due to old age. Often it is simply a sign of a sad emotional state. 

小题1: This passage is mainly about _______.

A．what caused mental decline

B．a new discovery about mental decline

C．the difference between middle-aged and older persons

D．how Dr Jarvik studied mental functioning of the twins小题2:The word “psychiatry” in paragraph 1 most probably means _______.

A．the study of diseases of the mind

B．the study of physical diseases

C．the study of twins’ growth

D．the study of human behavior小题3:More often than not, what we call mental decline is actually a sign of _______.

A．a worsening state of health

B．old age

C．nervous tension

D．a state of unhappiness

常用的修井转盘按结构形式分为（）。

A、船形底座转盘、轴传动转盘

B、法兰底座转盘、链条传动转盘

C、船形底座转盘、法兰底座转盘

D、轴传动转盘和链条传动转盘

股骨粗隆间骨折和股骨颈骨折多见于（）

A.青壮年

B.青少年

C.儿童

D.老年人

E.儿童和老人