Directions: Read the following passage and choose the most suitable heading from A—F for each paragraph. There is one extra heading which you do not need．       
A．The results explained why time passes quickly when we are dealing with more tasks
B．Time flies when you are having fun and drags when you are bored．
C．Volunteers were told to finish three different tasks in the study．
D．There are areas of the brain having the function of estimating time．
E．Concentrating on time passing is probably a more accurate perception of reality
F．Focusing on' the duration or the color the of image makes trips speed．

Scans have shown that patterns of activity in the brain change depending on how we focus on a task． Concentrating on time passing, as we do when bored, will trigger brain activity which will make it seem as though the clock is ticking more slowly．

In the study, 12 volunteers watched an image while researchers monitored their brain activity using MRI scans．Volunteers were given a variety of tasks．In one they were told to concentrate simply on the duration of an image, in another they were asked to focus on the color, and in a third they were asked to concentrate on both duration and color．

The results showed that a network of brain regions was activated when more subjects were paid attention to duration．It is thought that if the brain is busy focusing on many aspects of a task, then it has to spread its resources thinly, and pays less heed（注意） to time passing．Therefore, time passes without us really noticing it, and seems to go quickly．

However, if the brain is not stimulated in this way, it concentrates its full energies on monitoring the passing of time．This may make time seem to drag, but in fact the researchers found that the more volunteers concentrated on the duration of the images, the more accurate were their estimates of its duration．

Lead researcher Dr Jennifer Coull said many of the areas of the brain involved in estimating time were the same that played a key role in controlling movement, and preparing for action．She said this overlap suggests that the brain may make sense of time as intervals between movements, in much the same way as a musician marks time with his foot, or an athlete anticipates the sound of a starter's pistol（手枪）．