1 . If there had to be a father of handwashing in history, it would be Ignaz Semmelweis. While working at Vienna General hospital, the Hungarian doctor, faced with a situation in which maternal death (孕产妇死亡) in hospitals were significantly higher than local clinics, tried hard clues as to why.
Germs (细菌) were yet to be discovered, and it was still believed in the 1840s that disease was spread by bad smells in the air. So it didn’t seem a problem that trainee doctors hanging out of labs to dissect (解剖) human bodies would pop up to the maternity ward (产房) to deliver a baby without washing their hands.
Then an accidental finger cut by a knife during a dissection caused a doctor to die, seemingly of the same sign the mothers had been getting. Semmelweis assumed that something from the dead bodies was to blame, which might, through the hands of doctors, make their way into women’ s bodies during childbirth.
To test his theory, he ordered doctors to wash their hands and instruments in some chlorine solution. As a result, the death rate for new mothers dropped to about 1 percent, compared with that of as high as 18 percent before the experiment.
However, he faced great resistance, and met a sad end. People at that time didn’t think of themselves as sort of walking Petri dishes. And the majority of doctors then were from middle- or upper-class families, and thought of themselves as very clean people.
Over the next 40 years, a better understanding of germs developed, and attitudes to hygiene (卫生) gradually shifted. In 1876, the German scientist Robert Koch discovered the anthrax bacillus (炭疽), kicking off the new research field of medical bacteriology. Many more germs were later identified. Surgeons started to take handwashing seriously.
By the 1890s and into the early 1900s, handwashing moved from being something doctors did to something everybody had been told to do.
1. What was the situation like in the 1840s?| A．Germs might have been discovered then. |
| B．Women suffered from delivering babies then. |
| C．The air at that time was dirty and full of viruses. |
| D．People were unaware of how disease was spread. |
| A．Liquid. | B．Option. | C．Tissue. | D．Shell. |
| A．It was effective. | B．It was necessary. |
| C．It was ridiculous. | D．It was dangerous. |
| A．Steps to Protect Yourself |
| B．Disease Spreading by Your Hand |
| C．Hand Washing Critical in Fighting Viruses |
| D．The First Recorded Discovery of Handwashing |
2 . Here on Earth where most of us live, we spend about a third of everyday lying down sleeping and two-thirds standing or sitting in an upright position.
That's not really how it goes in space when people are weightless and the zero gravity environment causes more liquid to shift to the head. Faces get swollen, legs lose volume and appear to be smaller. Many astronauts have complained of eye and back problems after coming back down to Earth and its gravity.
And now scientists say they have discovered some new risks with long-term space flight. A study published recently in JAMA Network Open, a medical journal, examined 11 healthy astronauts who had been on the International Space Station for six months. Eight of them had unusual characteristics observed in their blood. For instance, six of the astronauts had reverse （反向的）blood flow from their heads.
The lead author of the study says he doesn't know if that's actually harmful. The blood is still leaving the head from other pathways, so flowing backwards through a jugular vein（颈静脉） may not be dangerous. But he says it does show a change in how blood moves through the body while in space.
Another issue the study found was blood clots （凝块）. One astronaut had one. Another showed signs of a partial blood clot. That is potentially harmful as the clots can block the flow of blood to the lungs. The astronaut who had one was treated for the rest of the spaceflight and made it home safely.
What does all this mean? Well, one researcher says these issues have probably been oc- curring since humans first went into space and that they would likely resolve themselves when astronauts came back down to Earth. Knowing about them now gives doctors something else to monitor when people leave our atmosphere.
1. What causes the physical problems for astronauts?| A．Sleeping for a long time. | B．The zero gravity environment. |
| C．Staying in the spaceship. | D．The shift in their bodies. |
| A．Four. | B．Three. | C．Two. | D．One. |
| A．It is a common problem. | B．It is a new kind of disease. |
| C．It is a threat to people's health. | D．It was first found by astronauts. |
| A．Doctors have a new task for astronauts |
| B．Zero gravity stops astronauts flying in space |
| C．It's dangerous for astronauts to fly into space |
| D．New risks are found in long-term space flight |
3 . Researchers at CU Boulder have developed a wearable device that changes the human body into a biological battery. The device is stretchy(弹性的) enough that you can wear it like a ring, sport band or any other thing that touches your skin. It also taps into a person's natural heat-employing thermoelectric generators to change the body's internal temperature into electricity. "In the future, we want to be able to power your wearable electronics without having to include a battery," said Jianliang Xiao, an associate professor at CU Boulder.
The concept may sound like something out of The Matrix film series, in which a race of robots have enslaved humans to harvest their precious organic energy. Xiao and his colleagues aren't that ambitious: Their devices can generate about 1 volt (伏特) of energy for every square centimeter of skin space-less volt per area than what most existing batteries provide but still enough to power electronics like watches or fitness trackers.
Scientists have previously experimented with similar wearable devices, but Xiao's is stretchy, can heal itself when damaged and is fully recyclable-making it a cleaner alternative to traditional electronics. "Whenever you use a battery, you're depleting(消耗) that battery and will, eventually, need to replace it," Xiao said. "The nice thing about our device is that you can wear it, and it provides you with constant power."
Just pretend that you're out for a jog. As you exercise, your body heats up, and that heat will radiate out to the cool air around you. Xiao's device captures that flow of energy rather than let it go to waste. "The thermoelectric generators are in close contact with the human body, and they can use the heat that would normally be sent into the environment," Xiao said.
1. What does Xiao expect of his device at present?| A．It will be used for medical purposes. |
| B．It will be made smaller and wearable. |
| C．It will change natural power into electricity. |
| D．It will supply constant power to wearable devices. |
| A．To give an explanation. | B．To make a comparison. |
| C．To introduce a topic. | D．To analyze the cause. |
| A．The strengths of Xiao's device. |
| B．The convenience of using a battery. |
| C．The replacement of wearable devices. |
| D．The development of traditional electronics. |
| A．It operates with plenty of power. |
| B．It is designed for practical use. |
| C．It benefits people's health in a way. |
| D．It's based on traditional electronics. |
