二阶系统的主要特征参数有（）、（）和（）。

下列说法正确的是（　　）

A．常温下，将pH=11的氨水稀释到原体积的10倍后，溶液的pH=10

B．为确定某酸．H₂A是强酸还是弱酸，可测NaHA溶液的pH，若pH＞7，则H₂A是弱酸；若pH＜7，则H₂A是强酸

C．用0.2000mol/L NaOH标准溶液滴定HCl与CH₃COOH的混合溶液（混合液中两种酸的浓度均约为0.1mol/L），至中性时，溶液中的酸未被完全中和

D．相同温度下，将足量氯化银固体分别放入相同体积的①蒸馏水②0.1mol/L盐酸 ③0.1mol/L氯化镁溶液④0.1mol/L硝酸银溶液中，则Ag⁺浓度：①＞④=②＞③

影响输卵管复通术效果的有关因素，下列哪项错误（）

A.与是否严格遵守复通术的适应证与禁忌证有关

B.显微吻合法成功率高于一般吻合法

C.与绝育的方法有关

D.与绝育的部位无关

E.与技术操作有无创伤有关

阅读理解。

                                           Decision-making under Stress

     A new review based on a research shows that stress affects the way the brain considers

the advantages and disadvantages, causing it to focus on pleasure and ignore the possible

negativeconsequences(results) of a decision.

     The research suggests that stress may change the way people make choices.

     "Stress affects how people learn," says Professor Mara Mather. "People learn better

about positive than negative outcomes under stress."

     For example, two recent studies looked at how people learned to connect images with

either rewards or punishments. In one experiment, some of the participants were first

stressed by having to give a speech and do difficult math problems in front of an audience;

in the other, some were stressed by having to keep their hands in ice water. In both cases,

the stressed participants remembered the rewarded material more accurately(精确) and

the punished material less accurately than those who hadn't gone through the stress.

     This phenomenon is likely not surprising to anyone who has tried to resist eating cookies

or smoking a cigarette while under stress -at those moments, only the pleasure associated

with such activities comes to mind. But the findings further suggest that stress may bring

about a double effect. Not only are rewarding experiences remembered better, but negative

consequences are also easily recalled.

     The research also found that stress appears to affect decision-making differently in men

and women. While both men and women tend to focus on rewards and less on consequences

under stress, their responses to risk turn out to be different.

     Men who had been stressed by the cold-water task tended to take more risks in the

experiment while women responded in the opposite way. In stressful situations in which

risk-taking can pay off big, men may tend to do better, when caution weighs more,

however, women will win.

     This tendency to slow down and become more cautious when decisions are risky might

also help explain why women are less likely to become addicted than men: they may more

often avoid making the risky choices that eventually harden into addiction.

1.We can learn from the passage that people under pressure tend to ______.

A. keep rewards better in their memory

B. recall consequences more effortlessly

C. make risky decisions more frequently

D. learn a subject more effectively

2.According to the research, stress affects people most probably in their ______.

A. ways of making choices

B. preference for pleasure

C. tolerance(容忍) of punishments

D. responses to suggestions

3. The research has proved that in a stressful situation, ______.

A. women find it easier to fall into certain habits

B. men have a greater tendency to slow down

C. women focus more on outcomes

D. men are more likely to take risks

老李沿着铁路散步，他每分钟走60米，迎面过来一列长300米的火车，他与车头相遇到与车尾相离共用了20秒，问火车的速度为多少米/秒( )

A．20

B．15

C．21

D．14

耐火砖砖缝厚度为Ⅱ类的，其砖缝厚应小于（）mm。

A.0.5

B.1

C.2

D.3