机组启动时，凝结水运行方式采用()。A、凝结水排至地沟； B、倒向除氧器； C、凝结水水

【选修3-4选做题】

如图所示，为一列水平向右传播的简谐横波在某一时刻的波形图，波速大小为0.6 m／s。P质点的平衡位置坐标为x＝0.96m。从该时刻（图中状态，此时刻波从O点刚好向右传播了一个波长的距离）开始计时，问：    

（1）经过多少时间，P质点第一次到达波峰?

（2）P质点第一次到达波峰时，通过的路程为多少?

有位诗人坐船远眺，写下了著名诗词：“满眼风光多闪烁，看山恰似走来迎，仔细看山山不动，是船行．”诗人在诗词中前后两次对山的运动进行描述，所选择的参照物分别是（　　）

A．风和水

B．船和地面

C．山和船

D．风和地面

佝偻病常需与呆小病鉴别。在血生化方面，可资鉴别的是（）

A.血钙

B.血磷

C.血碱性磷酸酶

D.甲状腺素T₄

E.甲状旁腺素

TB/T2634—1995标准规定，探头工作环境温度，超低温型为：（）。

The fact that blind people can "see" things using other parts of their bodies apart from their eyes may help us to understand our feelings about colour. If they can sense colour differences then perhaps we, too, are affected by colour unconsciously.

Manufacturers have discovered by trial and error that sugar sells badly in green wrappings, and that blue foods are considered unpleasant, and the cosmetics should never be packaged in brown. These discoveries have grown into a whole discipline of color psychology that now finds application in everything from fashion to interior decoration. Some of our preferences are clearly psychological Dark blue is the colour of the night sky and therefore associated with passivity and calm, while yellow is a day colour with associations of energy and incentive. For primitive man, activity during the day meant hunting and attacking, while he soon saw as red, the colour of blood and rage and the heat that came with effort. And green is associated with passive defence and self - preservation. Experiments have shown that colours, partly because of their psychological association, also have a direct psychological effect. People exposed to bright red show an increase in heartbeat, and blood pressure; red is exciting. Similar exposure to pure blue has exactly the opposite effect; it is a calming colour. Because of its exciting connotations (涵义) , red was chosen as the signal for danger, but closer analysis shows that a vivid yellow can produce a more basic state of alertness and alarm, so fire engines and ambulances in some advanced communities are now rushing around in bright yellow colours that stop the traffic dead.

Manufacturers found out that colour affects sales（）。

A. by experimenting with different colours

B. by experience over a long period of time

C. by trying out colour on blind people

D. by developing the discipline of colour psychology