简述切丝机液压传动系统的工作原理。

If you see someone drowning, speed is very important. Once you get him out of the water, if he isn't breathing, you have four minutes before his brain is completely destroyed. Support his neck, move his head back and press his chin upwards. This stops the tongue blocking the airway in the throat and is sometimes enough to get him breathing again. If that doesn't work, start mouth-to-mouth breathing. Press his nostrils (the two holes at the end of your nose, through which you breathe and smell things) together with your fingers. Open your mouth and take a deep breath. Blow into his lungs until his chest rises, then remove your mouth and watch his chest fall. Repeat twelve times a minute. Keep doing until professional help arrives.

To bring a child back to life, keep your lips around his mouth and gently blow into his mouth. Give the first four breaths as quickly as possible to fill the blood with oxygen. If, in spite of your efforts, he starts turning a blue-grey colour, and you can feel no pulse(脉搏), then pressing is the last chance of saving his life.

With arms straight, rock forwards, pressing down on the lower half of the breastbone. Don't be too hard or you may break a rib. Check how effective you are by seeing if his colour improves or his pulse becomes independent to your chest pressing. If this happens, stop the pressing. Otherwise continue until rescue arrives.

小题1:If you want to save someone drowning, you __________.

A．have to pull off his clothes first .

B．should try to get him out of water as quickly as possible.

C．should first make out who he is.

D．ought to throw a life coat to him first .小题2:Once a person stops breathing, it means ___________.

A．you have no more than 4 minutes to bring him to life again .

B．his brain is completely damaged .

C．he has passed away.

D．there is no way to save his life .小题3:To press his chin upwards is a way to _____________.

A．keep the tongue from blocking the airway in the throat .

B．prevent the tongue from stopping the airway in the throat .

C．wipe the tongue out of the throat .

D．see if he can possibly be saved .小题4:If the drowning boy has no pulse,_____________.

A．press his chin upwards is enough to get him breathing .

B．blow air into his mouth is sure to save his life .

C．press his nostrils together with your fingers can work .

D．press is the last chance of saving his life .小题5:Which of the following statement is true?

A．Don’t stop pressing his chest, if the drowning man starts breathing again.

B．If you see someone drowning, you must give him mouth-to-mouth breathing.

C．If a man does not breathe for four minutes, his brain will be completely destroyed.

D．When pressing, you can do it as hard as you can.

半径为l厘米的小圆在半径为5厘米的固定的大圆外滚动一周，小圆滚了几圈（）

A．4

B．5

C．6

D．7

电子工程洁净室的功能鉴定为“静态”是指（）。

A.洁净设施已经完成，所有动力系统接通并运行，生产设备并未运行，且有人员

B.洁净设施已经完成，所有动力系统接通并运行，生产设备已经安装并运行，但无人员

C.洁净设施没有完成，所有动力系统接通并运行，生产设备已经安装并运行，但无人员

D.洁净设施没有完成，所有动力系统接通并运行，生产设备并未运行，且无人员

在1787年的制宪会议上，富兰克林一直在琢磨刻在华盛顿座椅上的太阳是日出还是日落，当他含着激动的眼泪在宪法文本上签字后，他说：“现在我很高兴的知道，那是日出，而不是日落。”对材料中“日出”的理解最正确的是（）

A.赋予政府权力，有利于国家稳固

B.分权制衡，有利于维护民主制度

C.确定共和政体，促进美国经济发展

D.制定宪法，废除黑人奴隶制度

有效汇率