5 . The history of microbiology begins with Dutch cloth maker named Antoni van Leeuwenhoek, a man of no formal scientific education. In the late 1600s. Leeuwenhoek, inspired by the magnifying lenses（放大镜）he used to examine cloth, built some of the first-microscopes. He developed technique to improve the quality of tiny, rounded lenses, some of which could magnify an object up to 270 times. After removing some plaque from between his teeth and examining it under a lens, Leeuwenhoek found tiny twisting creatures, which he called “animalcules”.

His observations, which he reported to the Royal Society of London, are among the first descriptions of microbes（微生物）. Leeuwenhoek discovered an entire universe invisible to the human eye. He found different microbes in samples of pond water, rain water, and human blood. He gave the first description of red blood cells, observed plant tissue, examined muscle, and investigated the life cycle of insects.

Nearly two hundred years later, Leeuwenhock’s discovery of microbes helped French chemist and biologist Louis Pasteur to develop his “theory of disease”. This concept suggested that disease originates from tiny organisms attacking and weakening the body. Pasteur’s theory later helped doctors to fight infectious diseases including anthrax, diphtheria, polio, smallpox, tetanus, and typhoid. All these breakthroughs were the result of Leeuwenhoek’s original work. Leeuwenhoek did not foresee this legacy.

In a 1716 letter, he described his contribution to science this way: “My work, which I’ve done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a strong desire for knowledge, which I notice resides in me more than in most other men. And therefore; whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that the scientific community might be informed thereof.”

6 . Taste memory is a kind of interesting memory. It is not only the memory of the smell itself, but also the associative memory of the things related to the smell and the emotional memory related to the judgment of the likes and dislikes of the smell. In short, when we smell a familiar smell, our first reaction is to search for the possible source of the smell in our memory - a certain kind of food? Some kind of perfume? Someone? Some place? Even if we smell a strange smell, we will subconsciously look for the smell similar to the smell in our memory.

The particularity of taste is also closely related to our survival instinct - because taste is often associated with food. It is an important survival skill to judge the food's edibility by smell. I have been experimenting with taste aversion(厌恶) memory for a period of time - a taste that has never been encountered and cannot be identified as safe. If there are adverse physiological reactions after eating, I will instinctively avoid this taste the next time I encounter it. This kind of phenomenon will be restrained to a certain extent when it comes to the familiar taste of safety, which is called "potential inhibition", that is, the degree of aversion will be reduced. However, if a person is familiar with the safe taste and has a very serious reaction, this taste will be associated with painful memory, then even if he knows that the taste is safe, he will also involuntarily avoid the food or affect his appetite. This fully shows that taste is not a single memory, but mixed with a large number of other memories.

"People's memory of smell will never be forgotten" - I don't know the origin of this proposition, and it's   also too absolute to say that it will never be forgotten - in fact, many diseases lead to people's inability to smell smell, let alone their memory of smell. However, due to the particularity of taste, different taste can not only cause active memory, but also cause a variety of subconscious memory, and also bring a variety of physiological reactions in the body. Therefore, compared with other kinds of memory, it is not easy to forget, which is more reasonable.

7 . We love letters. Just as John Donne, a poet, _________ it, “Letters, to me and my friends mean _________ greetings; they get souls together. Thanks to letters, friends who are _________ speak.” He wrote these words nearly 400 years ago. Today, in the age of instant text message, social media, and email, they _________ ring truer than ever, because writing or receiving a letter has become such a _________ event.

A UK-wide survey undertaken by Sunday Times suggests that one in four of us has not _________ a letter for at least 10 years. That’s ten years without the bitter-sweet _________ of pacing the floor waiting for the _________; ten years without recognizing the handwriting on the envelope and eagerly _________ the letter to read its content.

We ____________ not get them any more, but we still love handwritten letters. In the same survey, one third of ____________ people interviewed say that they ____________ the content of sentimental (充满情感的) letters. Shouldn’t we make ____________ to give our friends and families what they will treasure forever? Ann Bickley went online in 2013 and offered to handwrite a letter to anyone who ____________ her. Her website received 50,000 ____________ in its first three months. Five years later, she is still the main ____________ behind one-million-lovely-letter.com and has personally written 4,000 letters offering hope and ____________ to strangers.

The thought behind a letter ____________ as much as its contents. “I never tell anyone that ____________ is going to be OK,” Ann Bickley says, “I am letting someone know that there is someone in the world who ____________ them.”

Who wouldn’t love to receive a letter like that? Let’s get writing!

8 . There are many colors in nature. But do you think that a color has weight? I think you'll say "no". But I'm afraid you are wrong. If you don't believe it, you may do a small experiment.

First, put two objects with the same weight into two boxes. Then cover the boxes. Third, wrap one box with a red piece of paper, the other one with white piece of paper. OK. Now hold the boxes with your hand one by one. It is certain that you will think the red one is a little heavier.

Why do you think so? A scientist found that different colors have different weights in man's mind. That is to say, every color has its own weight in our mind.

The scientist told us that colors also have smell. Can you smell the color? Of course not. Then why did the scientist say so? That is because every color stands for kind of light with a certain wavelength（波长）. It reaches our brain through sense organs.

According to this discovery scientists say that people accept the colors they like, and refuse the colors they hate. So your body and mind will be healthy by using the colors you like. Or you'll be nervous or even get ill. For example, you like blue and hate red. If you stay in a room with red windows, wallpaper and furniture for two hours, you'll feel you have been there for four hours. But if the room is blue, you'll feel you have been there for only an hour. And if a person walks out of a blue room and into a red room, his temperature will rise. That means our body temperature will change with different colors.

9 . Taking at least twenty minutes out of your day to walk or sit in a place that makes you feel in contact with nature will significantly lower your stress hormone levels. That's the finding of a study that has established for the first time the most effective amount of an urban nature experience. Healthcare professionals can use this discovery to prescribe (开药) “nature-pills" in the knowledge that they have a real measurable effect

"We know that spending time in nature reduces stress, but until now it was unclear how much is enough, how often to do it, or even what kind of nature experience will benefit us,” says Dr. Hunter, a lead author of this research. “Our study shows that for the greatest payoff, in terms of efficiently lowering levels of the stress hormone, you should spend 20 to 30 minutes sitting or walking in a place that provides you with a sense of nature.

To assist healthcare professionals looking for evidence-based guidelines on what exactly to distribute, Hunter and her colleagues designed an experiment that would give a realistic estimate of an effective amount.

Over an 8-week period, participants were asked to take a nature pill with a duration of 10 minutes or more, at least 3 times a week. Levels of stress hormone, were measured from saliva (唾液)samples taken before and after a nature pill, once every two weeks. The data revealed that just a twenty-minute nature experience was enough to significantly reduce stress levels.

Healthcare professionals can use our results as an evidence-based rule of thumb on what to put in a nature-pill prescription," said Hunter. "It provides the first estimates of how na- ture experiences impact stress levels in the context of normal daily life. It breaks new ground by addressing some of the complexities of measuring an effective nature amount."

10 . In a recent series of experiments at the University of California, researchers studied toddlers’ thinking about winners and losers, bullies (欺凌) and victims.

In the first experiment, toddlers (学步儿童) watched a scene in which two puppets (木偶) had conflicting goals: One was crossing a stage from right to left, and the other from left to right. The puppets met in the middle and stopped. Eventually one puppet bowed down and moved aside, letting the other one pass by. Then researchers asked the toddlers which puppet they liked. The result: 20 out of 23 toddlers picked the higher-status puppet — the one that did not bow or move aside. It seems that individuals can gain status for being dominant (占优势的) and toddlers like winners better than losers.

But then researchers had another question: Do toddlers like winners no matter how they win? So, researchers did another experiment very similar to the one described above. But this time, the conflict ended because one puppet knocked the other down and out of the way. Now when the toddlers were asked who they liked, the results were different: Only 4 out of 23 children liked the winner.

These data suggest that children already love a winner by the age of 21-31 months. This does not necessarily mean that the preference is inborn: 21 months is enough time to learn a lot of things. But if a preference for winners is something we learn, we appear to learn it quite early.

Even more interesting, the preference for winners is not absolute. Children in our study did not like a winner who knocked a competitor down. This suggests that already by the age of 21-31 months, children’s liking for winners is balanced with other social concerns, including perhaps a general preference for nice or helpful people over aggressive ones.

In a time when the news is full of stories of public figures who celebrate winning at all costs, these results give us much confidence. Humans understand dominance, but we also expect strong individuals to guide, protect and help others. This feels like good news.