A new UCLA psychology study provides （A）

e that being overweight makes people tired and lazy - not the other way around.

Life （B） s led by UCLA's Aaron Blaisdell placed 32 female rats on one of two diets for six months. The first， a standard rat's diet， consisted of ground corn and fish meal. The second， a kind of junk food diet， contained more sugar..

After just three months， the researchers observed a significant （C） d in the amount of weight the rats had gained， with the 16 on the junk food diet having become noticeably fatter. The （D） e also suggest that fatigue（疲勞）may result from a junk food diet.

As part of the study， the rats were given a task in which they were required to press a lever（杠桿）to receive a food or water （1） r . The overweight rats apparently got tired and lazy more easily than the lean rats. In a 30-minute session， the fatter rats took breaks that were nearly twice as long as the lean ones.

After six months， the rats' diets were switched， and the overweight rats were given the healthy diet for nine days. This （2） c ， however， didn't help reduce their （E） w or improve their lever responses. The reverse was also true： Placing the lean rats on the junk food diet for nine days didn't increase their weight noticeably or reduce their motivation on the lever task. These findings suggest that a pattern of consuming junk food is responsible for obesity （肥胖）and （3） f .

What are the （4） i for humans？

The overweight people are often lazy and lacking discipline. The researchers interpret their results as suggesting that the common idea that people become fat because they are lazy is wrong. The data suggest that diet-induced （5） o is a cause， rather than an effect， of laziness.

（A， B， C， D， E FOR CROSS， 1， 2， 3， 4， 5 FOR DOWN. The first letters of the absents were given）