Most of us seem to reach our peak of alertness (警觉) around noon. Soon after that, alertness declines, and sleepiness may set in by mid-afternoon.
Your short-term memory is best during the morning—in fact, about 15 percent more efficient than at any other time of day. So, students, take notice: when you are faced with a morning exam, it really does pay to review your notes right before the test is given.
However, long-term memory is different. Afternoon is the best time for learning materials that you want to recall days, weeks or months later. Politicians, business executives or others who must learn speeches would be smart to do their memorizing during that time of day. You should try to do most of your studying in the afternoon, rather than late at night. Many students believe they memorize better while burning the midnight oil because their short-term recall is better during the early hours of the morning than in the afternoon. But short-term memory won’t help them much several days later, when they face the exam.
By contrast, we tend to do best on tasks related to the process of knowing, understanding, and learning numbers during the morning hours.
What about sports? During afternoon and early evening, you’re able to react the quickest to an outside stimulus—like a baseball speeding toward you. Studies have also shown that late in the day, when your body temperature is peaking, you will consider PE easier and less tiring—whether it actually is or not. That means you are more likely to work harder during a late afternoon or early evening workout, and therefore benefit more from it.  
In fact, all of your senses—taste, sight, hearing, touch and smell—may be at their keenest during late afternoon and early evening. That could be why dinner usually tastes better to us than breakfast.
While all of us follow the same general pattern of ups and downs, the exact timing varies from person to person. It all depends on how your “biological” day is structured. Each of us can increase our knowledge about our individual rhythms. Learn how to listen to the inner beats of your body; let them set the pace of your day. You will live a healthier and happier life.
What does the underlined “it really does pay” mean?

A．It will cost a lot.	B．It requires price.
C．It is very painful.	D．It is worthwhile.

If there is an English exam two weeks later, you should go over English ____________ for days before that.

A．in the afternoon	B．in the late evening
C．in the early morning	D．right before the exam

From the passage, it can be inferred that ______________.

A．we eat more food at noon

B．we feel most tired if we exercise in the evening

C．it is a good choice to study math in the morning

D．we feel most sleepy before noon

Which would be the best title for the passage?

A．What’s Your Best Time of the Day for Different Tasks

B．How to Live a Healthier and Happier Life

C．How to Study Efficiently

D．How to Keep Your Best State of Learning