Scientists are not sure how the brain follows the tracks of time．One theory holds that it has a group of cells specialized to record the intervals （间隔）of time, while another theory holds that some neural processes （神经突）act as an inside clock．
Whichever theory it may be, studies find, the cells have a poor grasp of longer interval．Time does seem to slow during an empty afternoon and race when the brain focuses on challenging work．Stimulants （兴奋剂）, including caffeine, tend to make people feel as if．time is passing faster; complex jobs, like doing taxes, can seem to drag on longer than they actually do．And  emotional  events — a breakup, a promotion, a transformative trip abroad —tend to be sensed as more recent than they actually are, by months or even years．In short, some psychologists say, the findings support the philosopher Martin Heidegger' s observation that time "persists merely as a consequence of the events taking place in it．"
Now researchers are finding that the opposite thing may also be true: if very few events come to mind, then the sense of time does not persist; the brain shortens the interval that has passed．
In one classic experiment, a French explorer named Michel Siffre lived in a cave for two months, cut off from the rhythms of night and day and man-made clocks．He appeared then, convinced that he had been isolated for only 25 days．Left to its own devices, the brain tends to shorten time．
In earlier work, researchers found  that a similar case at work in people’s judgment of intervals that last only moments．Relatively infrequent stimuli, like flashes or tones, tend to increase the speed of the brain' s internal pacemaker．
On an obvious level, these kinds of findings offer an explanation for why other people' s children seem to grow up so much faster than one's own．Involved parents are all too well aware of first step in their own children; however, seeing a cousin's child once every few years, without bothering memories, shortens the time．
What can we infer from the first paragraph?

A．Scientists have agreed about how the brain records time．

B．Scientists all think that some cells record the intervals of time．

C．Scientists haven't agreed on how the brain records time．

D．Scientists all hold the theory that neural processes are an inside clock．

According．to Paragraph 3, if we have few things to do, the brain will____．

A．make the intervals of time long

B．make the intervals of time short

C．keep a state of rest

D．stop working

Which of the following is TRUE according to the passage?

A．Michel Siffre didn' t think he had stayed in the cave for as long as two months．

B．Parents tend to think their own children grow faster than others．

C．Michel Diffre actually stayed in the cave for twenty-five days．

D．Children usually bring bad memories to their parents．

In which column of a newspaper can we find this passage?

A．Social news	B．Community activities
C．Science	D．Children s life