单项选择题A．It increased the students’ white blood cell count.B．It increased some students’ energy level.C．It improved the students’ ability to play musical instruments.D．It released a natural painkiller in some students’ bodies.

单项选择题A．Jack has often had to wait for Shelly.B．Jack has made others wait before.C．Jack doesn’t usually make people wait.D．Jack was playing a trick.

单项选择题A．Keep the party small.B．He suggests only he and the woman should arrange it.C．He suggests that they only have one party.D．He suggests that they keep it a secret.

单项选择题A．They are more likely to damage the cave.B．It’s hard for them to stay awake.C．They tend to break their equipment.D．They may imagine seeing things that aren’t really there.

单项选择题A．Music they like can relieve depression but distract attention.B．Music they like can reduce stress and improve concentration.C．Classical music and rock-and-roll increases their heart rate and expands the breathing.D．Wearing headphones can help concentrate when they are performing operations.

单项选择题A．Take the job offer.B．Try another job.C．Bargain a bit better.D．Concentrate on her studies.

单项选择题A．Repeat it aloud.B．Write it down.C．Make a mental picture of it.D．Practice recalling it.

单项选择题A．To replace physical therapy.B．To control brain seizures.C．To prevent heart disease.D．To relieve tension.

单项选择题A．It’s easy to locate.’B．It’s in a very windy area.C．It’s exceptionally beautiful.D．It’s partially covered by water.

单项选择题A．The need to exercise the memory.B．How the brain differs from other body tissues.C．The unconscious learning of a physical activity.D．How nerves control body movement.