According to the reading, what makes it difficult for researchers to know if an energy drink gives people energy?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 35.

FOR A QUICK PICKUP

       It used to be that people would drink coffee or tea in the morning to pick them up and get them going for the day. Then cola drinks hit the market. With lots of caffeine and sugar, these beverages soon became the pick-me-up of choice for many adults and teenagers. Now drink companies are putting out so-called “energy drinks.” These

beverages have the specific aim of giving tired consumers more energy.

       One example of a popular energy drink is Red Bull. The company that puts out this beverage has stated in interviews that Red Bull is not a thirst quencher. Nor is it meant to be a fluid replacement drink for athletes. Instead, the beverage is meant to revitalize a tired consumer’s body and mind. In order to do this, the makers of Red Bull, and other energy drinks, typically add vitamins and certain chemicals to their beverages. The added chemicals are like chemicals that the body naturally produces for energy. The vitamins, chemicals, caffeine, and sugar found in these beverages all seem like a sure bet to give a person energy.

       Health professionals are not so sure, though. For one thing, there is not enough evidence to show that all of the vitamins added to energy drinks actually raise a person’s energy level. Another problem is that there are so many things in the beverages. Nobody knows for sure how all of the ingredients in energy drinks work together.

       Dr. Brent Bauer, one of the directors at the Mayo Clinic in the US, cautions people about believing all the claims energy drinks make. He says, “It is plausible if you put these twelve things together, you will get a good result.” However, Dr. Bauer adds the mix of ingredients could also have a negative impact on the body. “We just don’t know at this

point,” he says.

What is the main idea of the reading?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

        People who daydream are often thought of in negative terms, such as being lazy or not doing what they should be doing. However, scientists who study the brain have learned many interesting things, especially from studying the brains of daydreamers. In fact, far from being a waste of time, some scientists believe that daydreaming is a healthy and useful activity for all of our brains.

        In order to study the brain, scientists use special devices that scan the brain and show pictures of which parts of the brain are active at certain times. By using this technique, they proved that when a person is daydreaming, the device will show a distinct pattern of activity in the brain called the “default” mode of thinking. In the default mode, the top or outside part of the brain is very active. Actually, several regions of the brain are interacting in this mode. Some scientists describe this mode as a time when the brain focuses on itself rather than focusing on the environment around the person. Typically, this occurs when a person is doing simple, tedious work or performing routine actions that don’t need much attention, like walking to school or cooking simple foods. People tend to daydream during such activities.

        The importance of daydreaming lies in developing both creative and social skills. When the mind is not engaged in dealing with one’s immediate situation or problem, then it is free to wonder about things. A time of wandering allows the mind to create things. New inventions may be imagined, or possible solutions to a problem can be planned. For example, solutions for problems in relationships with other people may come to mind. In fact, most daydreams involve situations with others. Perhaps these are daydreams based on memories of the past, or daydreams of what might be in the future. In either case, daydreams help us develop the appropriate skills we can use in real interactions with others.

         As neurologist Dr. Marcus Raichle of Washington University explains: “When you don’t use a muscle, that muscle really isn’t doing much. But when your brain is supposedly doing nothing and daydreaming, it’s really doing a tremendous amount.” During the so-called “resting state” the brain isn’t resting at all!

What does the passage mainly discuss?