When you start working on something but don't finish it, thoughts of the unfinished work continue to jump  into your mind even when you've moved on to other things. Psychologists (心理学家) refer to this psychological phenomenon as the Zeigarnik effect. The effect was first observed by a Russian psychologist named Bluma Zeigarnik. While sitting in a busy restaurant in Vienna, she noted the waiters had better memories of unpaid orders. Once the bill was paid, however, the waiters had difficulty remembering the exact details of the orders.
In research, participants were asked to complete simple tasks such as putting together puzzles, or solving math problems. Half of the participants were interrupted halfway through these tasks. After an hour-long delay, Zeigarnik asked the participants to give an account of what they'd been working on. She discovered that those who had their work interrupted were twice as likely to remember what they had been doing as those who had actually completed the tasks.
We can use this effect to our advantage. For example, if you're struggling to memorize something important, momentary interruptions might actually work to your advantage. Rather than simply remember the information  over and over again, review it several times and then take a break. While you're focusing on other things, you'll find yourself mentally returning to the information you were studying.
We often put off tasks until the last moment, only completing them in a rush at the last possible moment. Unfortunately, this tendency can lead to heavy stress and even poor performance. One way to overcome this is to put the Zeigarnik effect to work. Start by taking the first step, no matter how small. Once you've begun—but not finished—your work, you'll find yourself thinking of the task until, at last, you finish it. You might not finish it all  at once, but each small step you take puts you closer to your final goal.

28.What does the Zeigarnik effect refer to?
A.Waiters tend to have good memories.
B.Once interrupted, one will forget things easily.
C.Most people can't focus on one thing for a long time.
D.People remember unfinished tasks better than completed ones.
29.What were all the participants required to do in the study?
A.Describe their tasks.
B.Express their feelings.
C.Test their intelligence.
D.Design simple activities.
30.How should we study according to the Zeigarnik effect?
A.Repeat over and over again.
B.Divide up our study session.
C.Focus on several tasks at a time.
D.Have enough rest before studying.
31.What's the main idea of the last paragraph?
A.How to get rid of heavy stress.
B.Why we should set a final goal.
C.How to break the habit of delaying work.
D.Why we always complete tasks in a rush.

28-31 DABC