Nowadays, many of us track our steps with smart watches, pedometers (计步器) or phone apps and are of course thrilled when we reach that all-important daily goal of 10,000 steps. You might_______that this number has appeared after years of research.

The_______number ''10,000'' dates back to a marketing campaign_______shortly before the start of the1964 Tokyo Olympic Games. A company began_______a pedometer called the Manpo-kei: ''man'' meaning 10,000, ''po'' meaning_______and ''kei'' meaning meter. It was hugely _______and the number seems to have stuck. Many buyers are appealed by the new device.

Since then, studies have_______the health benefits of 5,000 with 10,000 steps and, not _______，the higher number is better. But until recently, all the_______between hadn’t been studied. I-Min Lee, a professor of________at Harvard Medical School, and her team________a group of more than 16,000 women in their seventies. Each woman spent a week________a device to measure movement during________hours. When they________the women up an average of four years and three months later, 504 died. How many steps do you think the people alive had been doing? In fact, the average number for________was only 5,500 but not 10,000. Women who took more than 4,000 steps a________were significantly more likely to still be alive than those who did only 2,700 steps. It's surprising that such a small________could have consequences for longevity (寿命).

However, physical conditions________from person to person, and we should do it wisely. So count if you find it ________ you, but remember there’s nothing special about 10,000 steps. Set the goal that is________for you.

Famous people often say that the key to becoming both happy and successful is to “do what you love”. But mastering a skill, even one that you deeply love, _________ a huge amount of dull work. Anyone who wants to master a skill must run through the cycle of practice, _________ feedback, modification, and increasing improvement again, again and again. Some people seem able to concentrate on practicing an activity like this for years and take pleasure in their gradual improvement. Yet others find this kind of focused, time-intensive work to be _________ or boring. Why?

The difference may _________ the ability to enter into state of “flow,” the feeling of being completely involved in what you are doing. Since Mihaly Csikszentmihalyi developed the _________ of flow in the 1970’s, it has been a mainstay of positive-psychology research. Flow states can happen in the course of any activity, and they are most common when a task has well-defined goals and is at a(n) _________ skill level.

Csikszentmihalyi suggested that those who most _________ entered into flow states had an “autotelic (自成目的的) personality” — a disposition to seek out challenges and get into a state of flow. While those without such a personality see difficulties, autotelic individuals see opportunities to build skills. With their capacity for “disinterested interest”, such people have a great _________ over others in developing their innate abilities.

Fortunately for those of us who aren’t necessarily blessed with an autotelic personality, there is evidence that flow states can be _________ by environmental factors. By giving ourselves unstructured, open-ended time, minimal __________, and a task set at a moderate level of difficulty, we may be able to love what we’re doing.

Marmoset monkeys exist on a branch of the evolutionary tree that is distinct from the one that led to humans. But they constantly _______ researchers with social behavior that seems pretty highly evolved. Their social organization and _______ practices could have been the model for the phrase “It takes a village.” A dominant male and female breed, and their babies are carefully looked after by _______ family members who then aren’t free to breed themselves.

A new study further _______ the marmoset’s reputation for admirable community values. Researchers report that these caregivers share their food more generously with little ones _______ than when they’re surrounded by the watchful eyes of other community members. In complex societies where individuals band together for mutual protection, researchers have come up with a few widely accepted explanations for _______ behavior. But specific acts, like sharing a delicious cricket (蟋蟀) with a begging baby marmoset, seem to need more specific explanation.

One possibility is that an individual practices _______ as a means of enhancing his status among peers. By presenting that he is so well gifted with material goods that he can give some away, this do-gooder enhances his power within the group. That, in turn, may _______ prospective mates.

The other explanation for charitable behavior _______ that kindnesses extended to others are simply the fees of group membership, which offers some future promise of a chance to mate.__________ to share would result in exclusion from the group and a loss of potential partners.   

Scientists call this the “pay to stay” model. Importantly, for both of these models to work, acts of kindness must have a(n) __________. That suggests you would see more sharing in group settings; away from judging eyes, a caregiver might be more likely to keep food for himself or herself. And yet, in 2,581 tests conducted with 31 adult and 14 baby marmosets, the __________ appeared to be true.

Anthropologists (人类学家) from the University of Zurich carefully documented how often, in groups and in conditions that found caregiver and baby separated from the crowd, an adult would share his or her cricket. When alone with a baby __________ for a taste, adult marmosets shared their cricket 85% of the time. When in a group, caregivers offered up their cricket 67% of the time.” Our results show that helping in common marmosets is not driven by__________management or punishment avoidance, “the study authors reported. Rather, it is driven by a deep-down ____________ to help that is more strongly expressed when individuals are alone with young.”